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r368 r411 1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 17. File and Record Locking</title><link rel="stylesheet" href="../samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.7 5.2"><link rel="home" href="index.html" title="The Official Samba 3.3.x HOWTO and Reference Guide"><link rel="up" href="optional.html" title="Part III. Advanced Configuration"><link rel="prev" href="AccessControls.html" title="Chapter 16. File, Directory, and Share Access Controls"><link rel="next" href="securing-samba.html" title="Chapter 18. Securing Samba"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 17. File and Record Locking</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="AccessControls.html">Prev</a> </td><th width="60%" align="center">Part III. Advanced Configuration</th><td width="20%" align="right"> <a accesskey="n" href="securing-samba.html">Next</a></td></tr></table><hr></div><div class="chapter" title="Chapter 17. File and Record Locking"><div class="titlepage"><div><div><h2 class="title"><a name="locking"></a>Chapter 17. File and Record Locking</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Jeremy</span> <span class="surname">Allison</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jra@samba.org">jra@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Jelmer</span> <span class="othername">R.</span> <span class="surname">Vernooij</span></h3><div class="affiliation"><span class="orgname">The Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jelmer@samba.org">jelmer@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="othername">H.</span> <span class="surname">Terpstra</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jht@samba.org">jht@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Eric</span> <span class="surname">Roseme</span></h3><div class="affiliation"><span class="orgname">HP Oplocks Usage Recommendations Whitepaper<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:eric.roseme@hp.com">eric.roseme@hp.com</a>></code></p></div></div></div></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="locking.html#id2621671">Features and Benefits</a></span></dt><dt><span class="sect1"><a href="locking.html#id2621768">Discussion</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2622026">Opportunistic Locking Overview</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2623031">Samba Oplocks Control</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2623125">Example Configuration</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2623539">MS Windows Oplocks and Caching Controls</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2623726">Workstation Service Entries</a></span></dt><dt><span class="sect2"><a href="locking.html#id2623748">Server Service Entries</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2623814">Persistent Data Corruption</a></span></dt><dt><span class="sect1"><a href="locking.html#id2623839">Common Errors</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2623907">locking.tdb Error Messages</a></span></dt><dt><span class="sect2"><a href="locking.html#id2623937">Problems Saving Files in MS Office on Windows XP</a></span></dt><dt><span class="sect2"><a href="locking.html#id2623962">Long Delays Deleting Files over Network with XP SP1</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2623993">Additional Reading</a></span></dt></dl></div><p>2 <a class="indexterm" name="id26 21660"></a>1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 17. File and Record Locking</title><link rel="stylesheet" href="../samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.74.0"><link rel="home" href="index.html" title="The Official Samba 3.3.x HOWTO and Reference Guide"><link rel="up" href="optional.html" title="Part III. Advanced Configuration"><link rel="prev" href="AccessControls.html" title="Chapter 16. File, Directory, and Share Access Controls"><link rel="next" href="securing-samba.html" title="Chapter 18. Securing Samba"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 17. File and Record Locking</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="AccessControls.html">Prev</a> </td><th width="60%" align="center">Part III. Advanced Configuration</th><td width="20%" align="right"> <a accesskey="n" href="securing-samba.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="locking"></a>Chapter 17. File and Record Locking</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Jeremy</span> <span class="orgname">Samba Team</span> <span class="surname">Allison</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jra@samba.org">jra@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Jelmer</span> <span class="othername">R.</span> <span class="orgname">The Samba Team</span> <span class="surname">Vernooij</span></h3><div class="affiliation"><span class="orgname">The Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jelmer@samba.org">jelmer@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">John</span> <span class="othername">H.</span> <span class="orgname">Samba Team</span> <span class="surname">Terpstra</span></h3><div class="affiliation"><span class="orgname">Samba Team<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:jht@samba.org">jht@samba.org</a>></code></p></div></div></div></div><div><div class="author"><h3 class="author"><span class="firstname">Eric</span> <span class="orgname">HP Oplocks Usage Recommendations Whitepaper</span> <span class="surname">Roseme</span></h3><div class="affiliation"><span class="orgname">HP Oplocks Usage Recommendations Whitepaper<br></span><div class="address"><p><code class="email"><<a class="email" href="mailto:eric.roseme@hp.com">eric.roseme@hp.com</a>></code></p></div></div></div></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="locking.html#id2615585">Features and Benefits</a></span></dt><dt><span class="sect1"><a href="locking.html#id2615682">Discussion</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2615940">Opportunistic Locking Overview</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2616945">Samba Oplocks Control</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2617040">Example Configuration</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2617453">MS Windows Oplocks and Caching Controls</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2617640">Workstation Service Entries</a></span></dt><dt><span class="sect2"><a href="locking.html#id2617662">Server Service Entries</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2617728">Persistent Data Corruption</a></span></dt><dt><span class="sect1"><a href="locking.html#id2617754">Common Errors</a></span></dt><dd><dl><dt><span class="sect2"><a href="locking.html#id2617821">locking.tdb Error Messages</a></span></dt><dt><span class="sect2"><a href="locking.html#id2617852">Problems Saving Files in MS Office on Windows XP</a></span></dt><dt><span class="sect2"><a href="locking.html#id2617876">Long Delays Deleting Files over Network with XP SP1</a></span></dt></dl></dd><dt><span class="sect1"><a href="locking.html#id2617908">Additional Reading</a></span></dt></dl></div><p> 2 <a class="indexterm" name="id2615574"></a> 3 3 One area that causes trouble for many network administrators is locking. 4 4 The extent of the problem is readily evident from searches over the Internet. 5 </p><div class="sect1" title="Features and Benefits"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2621671"></a>Features and Benefits</h2></div></div></div><p>6 <a class="indexterm" name="id26 21679"></a>5 </p><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2615585"></a>Features and Benefits</h2></div></div></div><p> 6 <a class="indexterm" name="id2615593"></a> 7 7 Samba provides all the same locking semantics that MS Windows clients expect 8 8 and that MS Windows NT4/200x servers also provide. 9 9 </p><p> 10 <a class="indexterm" name="id26 21691"></a>10 <a class="indexterm" name="id2615605"></a> 11 11 The term <span class="emphasis"><em>locking</em></span> has exceptionally broad meaning and covers 12 12 a range of functions that are all categorized under this one term. 13 13 </p><p> 14 <a class="indexterm" name="id26 21707"></a>15 <a class="indexterm" name="id26 21714"></a>16 <a class="indexterm" name="id26 21721"></a>14 <a class="indexterm" name="id2615621"></a> 15 <a class="indexterm" name="id2615628"></a> 16 <a class="indexterm" name="id2615635"></a> 17 17 Opportunistic locking is a desirable feature when it can enhance the 18 18 perceived performance of applications on a networked client. However, the … … 24 24 it is intended to provide. 25 25 </p><p> 26 <a class="indexterm" name="id26 21740"></a>26 <a class="indexterm" name="id2615654"></a> 27 27 The MS Windows network administrator needs to be aware that file and record 28 28 locking semantics (behavior) can be controlled either in Samba or by way of registry 29 29 settings on the MS Windows client. 30 </p><div class="note" title="Note"style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>31 <a class="indexterm" name="id26 21755"></a>30 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 31 <a class="indexterm" name="id2615670"></a> 32 32 Sometimes it is necessary to disable locking control settings on the Samba 33 33 server as well as on each MS Windows client! 34 </p></div></div><div class="sect1" title="Discussion"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2621768"></a>Discussion</h2></div></div></div><p>35 <a class="indexterm" name="id26 21775"></a>36 <a class="indexterm" name="id26 21782"></a>34 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2615682"></a>Discussion</h2></div></div></div><p> 35 <a class="indexterm" name="id2615690"></a> 36 <a class="indexterm" name="id2615696"></a> 37 37 There are two types of locking that need to be performed by an SMB server. 38 38 The first is <span class="emphasis"><em>record locking</em></span> that allows a client to lock … … 40 40 that are specified when a file is open. 41 41 </p><p> 42 <a class="indexterm" name="id26 21803"></a>43 <a class="indexterm" name="id26 21810"></a>44 <a class="indexterm" name="id26 21817"></a>45 <a class="indexterm" name="id26 21824"></a>46 <a class="indexterm" name="id26 21831"></a>42 <a class="indexterm" name="id2615717"></a> 43 <a class="indexterm" name="id2615724"></a> 44 <a class="indexterm" name="id2615731"></a> 45 <a class="indexterm" name="id2615738"></a> 46 <a class="indexterm" name="id2615745"></a> 47 47 Record locking semantics under UNIX are very different from record locking under 48 48 Windows. Versions of Samba before 2.2 have tried to use the native fcntl() UNIX … … 54 54 many more differences, too many to be listed here. 55 55 </p><p> 56 <a class="indexterm" name="id26 21851"></a>57 <a class="indexterm" name="id26 21858"></a>56 <a class="indexterm" name="id2615765"></a> 57 <a class="indexterm" name="id2615772"></a> 58 58 Samba 2.2 and above implement record locking completely independently of the 59 59 underlying UNIX system. If a byte-range lock that the client requests happens … … 61 61 No other locks can be seen by UNIX, anyway. 62 62 </p><p> 63 <a class="indexterm" name="id26 21873"></a>64 <a class="indexterm" name="id26 21880"></a>63 <a class="indexterm" name="id2615787"></a> 64 <a class="indexterm" name="id2615794"></a> 65 65 Strictly speaking, an SMB server should check for locks before every read and write call on 66 66 a file. Unfortunately, with the way fcntl() works, this can be slow and may overstress … … 71 71 will make lock checking calls on <span class="emphasis"><em>every</em></span> read and write call. 72 72 </p><p> 73 <a class="indexterm" name="id26 21921"></a>73 <a class="indexterm" name="id2615836"></a> 74 74 You can also disable byte-range locking completely by using 75 75 <a class="link" href="smb.conf.5.html#LOCKING" target="_top">locking = no</a>. … … 78 78 tell clients that everything is okay. 79 79 </p><p> 80 <a class="indexterm" name="id26 21949"></a>81 <a class="indexterm" name="id26 21955"></a>82 <a class="indexterm" name="id26 21962"></a>83 <a class="indexterm" name="id26 21969"></a>84 <a class="indexterm" name="id26 21975"></a>85 <a class="indexterm" name="id26 21982"></a>86 <a class="indexterm" name="id26 21989"></a>80 <a class="indexterm" name="id2615863"></a> 81 <a class="indexterm" name="id2615869"></a> 82 <a class="indexterm" name="id2615876"></a> 83 <a class="indexterm" name="id2615883"></a> 84 <a class="indexterm" name="id2615890"></a> 85 <a class="indexterm" name="id2615896"></a> 86 <a class="indexterm" name="id2615903"></a> 87 87 The second class of locking is the <span class="emphasis"><em>deny modes</em></span>. These 88 88 are set by an application when it opens a file to determine what types of … … 91 91 <code class="constant">DENY_WRITE</code>, or <code class="constant">DENY_ALL</code>. There are also special compatibility 92 92 modes called <code class="constant">DENY_FCB</code> and <code class="constant">DENY_DOS</code>. 93 </p><div class="sect2" title="Opportunistic Locking Overview"><div class="titlepage"><div><div><h3 class="title"><a name="id2622026"></a>Opportunistic Locking Overview</h3></div></div></div><p>94 <a class="indexterm" name="id26 22034"></a>95 <a class="indexterm" name="id26 22041"></a>96 <a class="indexterm" name="id26 22048"></a>93 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2615940"></a>Opportunistic Locking Overview</h3></div></div></div><p> 94 <a class="indexterm" name="id2615948"></a> 95 <a class="indexterm" name="id2615955"></a> 96 <a class="indexterm" name="id2615962"></a> 97 97 Opportunistic locking (oplocks) is invoked by the Windows file system 98 98 (as opposed to an API) via registry entries (on the server and the client) … … 101 101 locally on the client that allows the following: 102 102 </p><div class="variablelist"><dl><dt><span class="term">Read-ahead:</span></dt><dd><p> 103 <a class="indexterm" name="id26 22071"></a>103 <a class="indexterm" name="id2615986"></a> 104 104 The client reads the local copy of the file, eliminating network latency. 105 105 </p></dd><dt><span class="term">Write caching:</span></dt><dd><p> 106 <a class="indexterm" name="id26 22090"></a>106 <a class="indexterm" name="id2616004"></a> 107 107 The client writes to the local copy of the file, eliminating network latency. 108 108 </p></dd><dt><span class="term">Lock caching:</span></dt><dd><p> 109 <a class="indexterm" name="id26 22108"></a>109 <a class="indexterm" name="id2616022"></a> 110 110 The client caches application locks locally, eliminating network latency. 111 111 </p></dd></dl></div><p> 112 <a class="indexterm" name="id26 22122"></a>113 <a class="indexterm" name="id26 22129"></a>114 <a class="indexterm" name="id26 22136"></a>112 <a class="indexterm" name="id2616036"></a> 113 <a class="indexterm" name="id2616043"></a> 114 <a class="indexterm" name="id2616050"></a> 115 115 The performance enhancement of oplocks is due to the opportunity of 116 116 exclusive access to the file even if it is opened with deny-none 117 117 because Windows monitors the file's status for concurrent access from 118 118 other processes. 119 </p><div class="variablelist" title="Windows Defines Four Kinds of Oplocks:"><p class="title"><b>Windows Defines Four Kinds of Oplocks:</b></p><dl><dt><span class="term">Level1 Oplock</span></dt><dd><p>120 <a class="indexterm" name="id26 22167"></a>121 <a class="indexterm" name="id26 22173"></a>122 <a class="indexterm" name="id26 22180"></a>123 <a class="indexterm" name="id26 22187"></a>119 </p><div class="variablelist"><p class="title"><b>Windows Defines Four Kinds of Oplocks:</b></p><dl><dt><span class="term">Level1 Oplock</span></dt><dd><p> 120 <a class="indexterm" name="id2616081"></a> 121 <a class="indexterm" name="id2616088"></a> 122 <a class="indexterm" name="id2616094"></a> 123 <a class="indexterm" name="id2616101"></a> 124 124 The redirector sees that the file was opened with deny 125 125 none (allowing concurrent access), verifies that no … … 129 129 operations on the cached local file. 130 130 </p><p> 131 <a class="indexterm" name="id26 22203"></a>132 <a class="indexterm" name="id26 22210"></a>133 <a class="indexterm" name="id26 22217"></a>134 <a class="indexterm" name="id26 22224"></a>131 <a class="indexterm" name="id2616117"></a> 132 <a class="indexterm" name="id2616124"></a> 133 <a class="indexterm" name="id2616131"></a> 134 <a class="indexterm" name="id2616138"></a> 135 135 If a second process attempts to open the file, the open 136 136 is deferred while the redirector "breaks" the original … … 146 146 the oplock break. 147 147 </p></dd><dt><span class="term">Level2 Oplock</span></dt><dd><p> 148 <a class="indexterm" name="id26 22262"></a>149 <a class="indexterm" name="id26 22269"></a>150 <a class="indexterm" name="id26 22276"></a>148 <a class="indexterm" name="id2616177"></a> 149 <a class="indexterm" name="id2616184"></a> 150 <a class="indexterm" name="id2616190"></a> 151 151 Performs like a Level1 oplock, except caching is only 152 152 operative for reads. All other operations are performed 153 153 on the server disk copy of the file. 154 154 </p></dd><dt><span class="term">Filter Oplock</span></dt><dd><p> 155 <a class="indexterm" name="id26 22296"></a>155 <a class="indexterm" name="id2616211"></a> 156 156 Does not allow write or delete file access. 157 157 </p></dd><dt><span class="term">Batch Oplock</span></dt><dd><p> 158 <a class="indexterm" name="id26 22315"></a>158 <a class="indexterm" name="id2616229"></a> 159 159 Manipulates file openings and closings and allows caching 160 160 of file attributes. 161 161 </p></dd></dl></div><p> 162 <a class="indexterm" name="id26 22329"></a>162 <a class="indexterm" name="id2616243"></a> 163 163 An important detail is that oplocks are invoked by the file system, not 164 164 an application API. Therefore, an application can close an oplocked … … 167 167 preparation for the subsequent open by the second process. 168 168 </p><p> 169 <a class="indexterm" name="id26 22345"></a>170 <a class="indexterm" name="id26 22352"></a>171 <a class="indexterm" name="id26 22359"></a>172 <a class="indexterm" name="id26 22366"></a>169 <a class="indexterm" name="id2616259"></a> 170 <a class="indexterm" name="id2616266"></a> 171 <a class="indexterm" name="id2616273"></a> 172 <a class="indexterm" name="id2616280"></a> 173 173 <span class="emphasis"><em>Opportunistic locking</em></span> is actually an improper name for this feature. 174 174 The true benefit of this feature is client-side data caching, and … … 180 180 client-side caching benefit is negated. 181 181 </p><p> 182 <a class="indexterm" name="id26 22388"></a>182 <a class="indexterm" name="id2616302"></a> 183 183 The actual decision that a user or administrator should consider is 184 184 whether it is sensible to share among multiple users data that will … … 186 186 Deciding when to cache or not cache data is the real question, and thus 187 187 oplocks should be treated as a toggle for client-side 188 caching. Turn it <span class="quote">“<span class="quote">on</span>”</span>when client-side caching is desirable and189 reliable. Turn it <span class="quote">“<span class="quote">off</span>”</span>when client-side caching is redundant,188 caching. Turn it “<span class="quote">on</span>” when client-side caching is desirable and 189 reliable. Turn it “<span class="quote">off</span>” when client-side caching is redundant, 190 190 unreliable, or counterproductive. 191 191 </p><p> 192 <a class="indexterm" name="id26 22413"></a>193 Oplocks is by default set to <span class="quote">“<span class="quote">on</span>”</span>by Samba on all192 <a class="indexterm" name="id2616327"></a> 193 Oplocks is by default set to “<span class="quote">on</span>” by Samba on all 194 194 configured shares, so careful attention should be given to each case to 195 195 determine if the potential benefit is worth the potential for delays. … … 197 197 where oplocks may be effectively configured. 198 198 </p><p> 199 <a class="indexterm" name="id26 22431"></a>200 <a class="indexterm" name="id26 22438"></a>199 <a class="indexterm" name="id2616346"></a> 200 <a class="indexterm" name="id2616352"></a> 201 201 Windows oplocks is a lightweight performance-enhancing 202 202 feature. It is not a robust and reliable protocol. Every … … 209 209 storm. This configuration will likely encounter problems with oplocks. 210 210 </p><p> 211 <a class="indexterm" name="id26 22458"></a>211 <a class="indexterm" name="id2616372"></a> 212 212 Oplocks can be beneficial to perceived client performance when treated 213 213 as a configuration toggle for client-side data caching. If the data … … 223 223 continuous data availability. 224 224 </p><p> 225 <a class="indexterm" name="id26 22480"></a>226 <a class="indexterm" name="id26 22487"></a>225 <a class="indexterm" name="id2616395"></a> 226 <a class="indexterm" name="id2616402"></a> 227 227 Windows client failover behavior is more at risk of application 228 228 interruption than other platforms because it is dependent upon an … … 234 234 require restarting. 235 235 </p><p> 236 <a class="indexterm" name="id26 22515"></a>237 <a class="indexterm" name="id26 22521"></a>238 <a class="indexterm" name="id26 22528"></a>236 <a class="indexterm" name="id2616429"></a> 237 <a class="indexterm" name="id2616435"></a> 238 <a class="indexterm" name="id2616442"></a> 239 239 If a client session has been caching writes and reads locally due to 240 240 oplocks, it is likely that the data will be lost when the … … 251 251 testing should be done with all affected applications with oplocks 252 252 enabled and disabled. 253 </p><div class="sect3" title="Exclusively Accessed Shares"><div class="titlepage"><div><div><h4 class="title"><a name="id2622552"></a>Exclusively Accessed Shares</h4></div></div></div><p>253 </p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616466"></a>Exclusively Accessed Shares</h4></div></div></div><p> 254 254 Oplocks is most effective when it is confined to shares 255 255 that are exclusively accessed by a single user, or by only one user at … … 260 260 Home directories are the most obvious examples of where the performance 261 261 benefit of oplocks can be safely realized. 262 </p></div><div class="sect3" title="Multiple-Accessed Shares or Files"><div class="titlepage"><div><div><h4 class="title"><a name="id2622572"></a>Multiple-Accessed Shares or Files</h4></div></div></div><p>262 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616487"></a>Multiple-Accessed Shares or Files</h4></div></div></div><p> 263 263 As each additional user accesses a file in a share with oplocks 264 264 enabled, the potential for delays and resulting perceived poor … … 272 272 the potential performance improvement is negated and eventually results 273 273 in a performance bottleneck. 274 </p></div><div class="sect3" title="UNIX or NFS Client-Accessed Files"><div class="titlepage"><div><div><h4 class="title"><a name="id2622603"></a>UNIX or NFS Client-Accessed Files</h4></div></div></div><p>275 <a class="indexterm" name="id26 22611"></a>276 <a class="indexterm" name="id26 22618"></a>274 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616518"></a>UNIX or NFS Client-Accessed Files</h4></div></div></div><p> 275 <a class="indexterm" name="id2616526"></a> 276 <a class="indexterm" name="id2616532"></a> 277 277 Local UNIX and NFS clients access files without a mandatory 278 278 file-locking mechanism. Thus, these client platforms are incapable of … … 284 284 If files are shared between Windows clients and either local UNIX 285 285 or NFS users, turn oplocks off. 286 </p></div><div class="sect3" title="Slow and/or Unreliable Networks"><div class="titlepage"><div><div><h4 class="title"><a name="id2622639"></a>Slow and/or Unreliable Networks</h4></div></div></div><p>287 <a class="indexterm" name="id26 22647"></a>288 <a class="indexterm" name="id26 22654"></a>289 <a class="indexterm" name="id26 22660"></a>286 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616553"></a>Slow and/or Unreliable Networks</h4></div></div></div><p> 287 <a class="indexterm" name="id2616561"></a> 288 <a class="indexterm" name="id2616568"></a> 289 <a class="indexterm" name="id2616575"></a> 290 290 The biggest potential performance improvement for oplocks 291 291 occurs when the client-side caching of reads and writes delivers the … … 302 302 oplocks if there is any chance of multiple users 303 303 regularly opening the same file. 304 </p></div><div class="sect3" title="Multiuser Databases"><div class="titlepage"><div><div><h4 class="title"><a name="id2622686"></a>Multiuser Databases</h4></div></div></div><p>305 <a class="indexterm" name="id26 22694"></a>306 <a class="indexterm" name="id26 22701"></a>307 <a class="indexterm" name="id26 22708"></a>304 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616601"></a>Multiuser Databases</h4></div></div></div><p> 305 <a class="indexterm" name="id2616608"></a> 306 <a class="indexterm" name="id2616615"></a> 307 <a class="indexterm" name="id2616622"></a> 308 308 Multiuser databases clearly pose a risk due to their very nature they are typically heavily 309 309 accessed by numerous users at random intervals. Placing a multiuser database on a share with oplocks enabled 310 310 will likely result in a locking management bottleneck on the Samba server. Whether the database application is 311 311 developed in-house or a commercially available product, ensure that the share has oplocks disabled. 312 </p></div><div class="sect3" title="PDM Data Shares"><div class="titlepage"><div><div><h4 class="title"><a name="id2622728"></a>PDM Data Shares</h4></div></div></div><p>313 <a class="indexterm" name="id26 22735"></a>314 <a class="indexterm" name="id26 22742"></a>315 <a class="indexterm" name="id26 22749"></a>316 <a class="indexterm" name="id26 22756"></a>317 <a class="indexterm" name="id26 22763"></a>312 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616642"></a>PDM Data Shares</h4></div></div></div><p> 313 <a class="indexterm" name="id2616649"></a> 314 <a class="indexterm" name="id2616656"></a> 315 <a class="indexterm" name="id2616663"></a> 316 <a class="indexterm" name="id2616670"></a> 317 <a class="indexterm" name="id2616677"></a> 318 318 Process data management (PDM) applications such as IMAN, Enovia, and Clearcase are increasing in usage with 319 319 Windows client platforms and therefore with SMB datastores. PDM applications manage multiuser environments for … … 323 323 application and PDM server to negotiate and maintain. It is appropriate to eliminate the client OS from any 324 324 caching tasks, and the server from any oplocks management, by disabling oplocks on the share. 325 </p></div><div class="sect3" title="Beware of Force User"><div class="titlepage"><div><div><h4 class="title"><a name="id2622797"></a>Beware of Force User</h4></div></div></div><p>326 <a class="indexterm" name="id26 22805"></a>325 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616711"></a>Beware of Force User</h4></div></div></div><p> 326 <a class="indexterm" name="id2616719"></a> 327 327 Samba includes an <code class="filename">smb.conf</code> parameter called <a class="link" href="smb.conf.5.html#FORCEUSER" target="_top">force user</a> that changes the user 328 328 accessing a share from the incoming user to whatever user is defined by the <code class="filename">smb.conf</code> variable. If oplocks is … … 333 333 </p><p> 334 334 Avoid the combination of the following: 335 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>335 </p><div class="itemizedlist"><ul type="disc"><li><p> 336 336 <a class="link" href="smb.conf.5.html#FORCEUSER" target="_top">force user</a> in the <code class="filename">smb.conf</code> share configuration. 337 </p></li><li class="listitem"><p>337 </p></li><li><p> 338 338 Slow or unreliable networks. 339 </p></li><li class="listitem"><p>339 </p></li><li><p> 340 340 Oplocks enabled. 341 </p></li></ul></div></div><div class="sect3" title="Advanced Samba Oplocks Parameters"><div class="titlepage"><div><div><h4 class="title"><a name="id2622885"></a>Advanced Samba Oplocks Parameters</h4></div></div></div><p>342 <a class="indexterm" name="id26 22893"></a>343 <a class="indexterm" name="id26 22900"></a>344 <a class="indexterm" name="id26 22907"></a>341 </p></li></ul></div></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616799"></a>Advanced Samba Oplocks Parameters</h4></div></div></div><p> 342 <a class="indexterm" name="id2616807"></a> 343 <a class="indexterm" name="id2616814"></a> 344 <a class="indexterm" name="id2616821"></a> 345 345 Samba provides oplock parameters that allow the 346 346 administrator to adjust various properties of the oplock mechanism to … … 351 351 <a class="link" href="smb.conf.5.html#OPLOCKCONTENTIONLIMIT" target="_top">oplock contention limit</a>. 352 352 </p><p> 353 <a class="indexterm" name="id26 22947"></a>353 <a class="indexterm" name="id2616861"></a> 354 354 For most users, administrators, and environments, if these parameters 355 355 are required, then the better option is simply to turn oplocks off. 356 The Samba SWAT help text for both parameters reads: <span class="quote">“<span class="quote">Do not change357 this parameter unless you have read and understood the Samba oplock code.</span>” </span>356 The Samba SWAT help text for both parameters reads: “<span class="quote">Do not change 357 this parameter unless you have read and understood the Samba oplock code.</span>” 358 358 This is good advice. 359 </p></div><div class="sect3" title="Mission-Critical, High-Availability"><div class="titlepage"><div><div><h4 class="title"><a name="id2622964"></a>Mission-Critical, High-Availability</h4></div></div></div><p>359 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2616878"></a>Mission-Critical, High-Availability</h4></div></div></div><p> 360 360 In mission-critical, high-availability environments, data integrity is 361 361 often a priority. Complex and expensive configurations are implemented … … 387 387 testing should be done with all affected applications with oplocks 388 388 enabled and disabled. 389 </p></div></div></div><div class="sect1" title="Samba Oplocks Control"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2623031"></a>Samba Oplocks Control</h2></div></div></div><p>389 </p></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2616945"></a>Samba Oplocks Control</h2></div></div></div><p> 390 390 Oplocks is a unique Windows file locking feature. It is 391 391 not really file locking, but is included in most discussions of Windows … … 409 409 synchronizing the contents of the entire file back to the server for a single change. 410 410 </p><p> 411 Level1 Oplocks (also known as just plain <span class="quote">“<span class="quote">oplocks</span>”</span>) is another term for opportunistic locking.411 Level1 Oplocks (also known as just plain “<span class="quote">oplocks</span>”) is another term for opportunistic locking. 412 412 </p><p> 413 413 Level2 Oplocks provides opportunistic locking for a file that will be treated as … … 437 437 Another factor to consider is the perceived performance of file access. If oplocks provide no 438 438 measurable speed benefit on your network, it might not be worth the hassle of dealing with them. 439 </p><div class="sect2" title="Example Configuration"><div class="titlepage"><div><div><h3 class="title"><a name="id2623125"></a>Example Configuration</h3></div></div></div><p>439 </p><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2617040"></a>Example Configuration</h3></div></div></div><p> 440 440 In the following section we examine two distinct aspects of Samba locking controls. 441 </p><div class="sect3" title="Disabling Oplocks"><div class="titlepage"><div><div><h4 class="title"><a name="id2623136"></a>Disabling Oplocks</h4></div></div></div><p>441 </p><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2617050"></a>Disabling Oplocks</h4></div></div></div><p> 442 442 You can disable oplocks on a per-share basis with the following: 443 443 </p><p> 444 </p><table border="0" summary="Simple list" class="simplelist"><tr><td> </td></tr><tr><td><em class="parameter"><code>[acctdata]</code></em></td></tr><tr><td><a class="indexterm" name="id2623163"></a><em class="parameter"><code>oplocks = False</code></em></td></tr><tr><td><a class="indexterm" name="id2623174"></a><em class="parameter"><code>level2 oplocks = False</code></em></td></tr></table><p>444 </p><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[acctdata]</code></em></td></tr><tr><td><a class="indexterm" name="id2617077"></a><em class="parameter"><code>oplocks = False</code></em></td></tr><tr><td><a class="indexterm" name="id2617089"></a><em class="parameter"><code>level2 oplocks = False</code></em></td></tr></table><p> 445 445 </p><p> 446 446 The default oplock type is Level1. Level2 oplocks are enabled on a per-share basis … … 449 449 Alternately, you could disable oplocks on a per-file basis within the share: 450 450 </p><p> 451 </p><table border="0" summary="Simple list" class="simplelist"><tr><td><a class="indexterm" name="id2623210"></a><em class="parameter"><code>veto oplock files = /*.mdb/*.MDB/*.dbf/*.DBF/</code></em></td></tr></table><p>451 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2617125"></a><em class="parameter"><code>veto oplock files = /*.mdb/*.MDB/*.dbf/*.DBF/</code></em></td></tr></table><p> 452 452 </p><p> 453 453 If you are experiencing problems with oplocks, as apparent from Samba's log entries, 454 454 you may want to play it safe and disable oplocks and Level2 oplocks. 455 </p></div><div class="sect3" title="Disabling Kernel Oplocks"><div class="titlepage"><div><div><h4 class="title"><a name="id2623231"></a>Disabling Kernel Oplocks</h4></div></div></div><p>455 </p></div><div class="sect3" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="id2617145"></a>Disabling Kernel Oplocks</h4></div></div></div><p> 456 456 Kernel oplocks is an <code class="filename">smb.conf</code> parameter that notifies Samba (if 457 457 the UNIX kernel has the capability to send a Windows client an oplock … … 466 466 basis in the <code class="filename">smb.conf</code> file. 467 467 </p><p> 468 </p><table border="0" summary="Simple list" class="simplelist"><tr><td><a class="indexterm" name="id2623271"></a><em class="parameter"><code>kernel oplocks = yes</code></em></td></tr></table><p>468 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2617185"></a><em class="parameter"><code>kernel oplocks = yes</code></em></td></tr></table><p> 469 469 The default is no. 470 470 </p><p> … … 481 481 <code class="filename">smb.conf</code> file as shown in <a class="link" href="locking.html#far1" title="Example 17.1. Share with Some Files Oplocked">“Share with Some Files Oplocked”</a>. 482 482 </p><p> 483 </p><div class="example"><a name="far1"></a><p class="title"><b>Example 17.1. Share with Some Files Oplocked</b></p><div class="example-contents"><table border="0" summary="Simple list" class="simplelist"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2623347"></a><em class="parameter"><code>veto oplock files = /filename.htm/*.txt/</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[share_name]</code></em></td></tr><tr><td><a class="indexterm" name="id2623368"></a><em class="parameter"><code>veto oplock files = /*.exe/filename.ext/</code></em></td></tr></table></div></div><p><br class="example-break">483 </p><div class="example"><a name="far1"></a><p class="title"><b>Example 17.1. Share with Some Files Oplocked</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2617262"></a><em class="parameter"><code>veto oplock files = /filename.htm/*.txt/</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[share_name]</code></em></td></tr><tr><td><a class="indexterm" name="id2617283"></a><em class="parameter"><code>veto oplock files = /*.exe/filename.ext/</code></em></td></tr></table></div></div><p><br class="example-break"> 484 484 </p><p> 485 485 <a class="link" href="smb.conf.5.html#OPLOCKBREAKWAITTIME" target="_top">oplock break wait time</a> is an <code class="filename">smb.conf</code> parameter 486 486 that adjusts the time interval for Samba to reply to an oplock break request. Samba recommends: 487 <span class="quote">“<span class="quote">Do not change this parameter unless you have read and understood the Samba oplock code.</span>”</span> 487 “<span class="quote">Do not change this parameter unless you have read and understood the Samba oplock code.</span>” 488 488 Oplock break wait time can only be configured globally in the <code class="filename">smb.conf</code> file as shown: 489 489 </p><p> 490 </p><table border="0" summary="Simple list" class="simplelist"><tr><td><a class="indexterm" name="id2623426"></a><em class="parameter"><code>oplock break wait time = 0 (default)</code></em></td></tr></table><p>490 </p><table class="simplelist" border="0" summary="Simple list"><tr><td><a class="indexterm" name="id2617340"></a><em class="parameter"><code>oplock break wait time = 0 (default)</code></em></td></tr></table><p> 491 491 </p><p> 492 492 <span class="emphasis"><em>Oplock break contention limit</em></span> is an <code class="filename">smb.conf</code> parameter that limits the 493 493 response of the Samba server to grant an oplock if the configured 494 494 number of contending clients reaches the limit specified by the parameter. Samba recommends 495 <span class="quote">“<span class="quote">Do not change this parameter unless you have read and understood the Samba oplock code.</span>”</span> 495 “<span class="quote">Do not change this parameter unless you have read and understood the Samba oplock code.</span>” 496 496 Oplock break contention limit can be enabled on a per-share basis, or globally for 497 497 the entire server, in the <code class="filename">smb.conf</code> file as shown in <a class="link" href="locking.html#far3" title="Example 17.2. Configuration with Oplock Break Contention Limit">“Configuration with Oplock Break Contention Limit”</a>. 498 498 </p><p> 499 </p><div class="example"><a name="far3"></a><p class="title"><b>Example 17.2. Configuration with Oplock Break Contention Limit</b></p><div class="example-contents"><table border="0" summary="Simple list" class="simplelist"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2623500"></a><em class="parameter"><code>oplock break contention limit = 2 (default)</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[share_name]</code></em></td></tr><tr><td><a class="indexterm" name="id2623521"></a><em class="parameter"><code>oplock break contention limit = 2 (default)</code></em></td></tr></table></div></div><p><br class="example-break">500 </p></div></div></div><div class="sect1" title="MS Windows Oplocks and Caching Controls"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2623539"></a>MS Windows Oplocks and Caching Controls</h2></div></div></div><p>499 </p><div class="example"><a name="far3"></a><p class="title"><b>Example 17.2. Configuration with Oplock Break Contention Limit</b></p><div class="example-contents"><table class="simplelist" border="0" summary="Simple list"><tr><td> </td></tr><tr><td><em class="parameter"><code>[global]</code></em></td></tr><tr><td><a class="indexterm" name="id2617414"></a><em class="parameter"><code>oplock break contention limit = 2 (default)</code></em></td></tr><tr><td> </td></tr><tr><td><em class="parameter"><code>[share_name]</code></em></td></tr><tr><td><a class="indexterm" name="id2617435"></a><em class="parameter"><code>oplock break contention limit = 2 (default)</code></em></td></tr></table></div></div><p><br class="example-break"> 500 </p></div></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2617453"></a>MS Windows Oplocks and Caching Controls</h2></div></div></div><p> 501 501 There is a known issue when running applications (like Norton Antivirus) on a Windows 2000/ XP 502 502 workstation computer that can affect any application attempting to access shared database files … … 506 506 the Windows 2000/XP operating system will attempt to increase performance by locking the 507 507 files and caching information locally. When this occurs, the application is unable to 508 properly function, which results in an <span class="quote">“<span class="quote">Access Denied</span>”</span>508 properly function, which results in an “<span class="quote">Access Denied</span>” 509 509 error message being displayed during network operations. 510 510 </p><p> … … 513 513 have oplocks disabled in order to minimize the risk of data file corruption. 514 514 This includes Windows 9x/Me, Windows NT, Windows 200x, and Windows XP. 515 <sup>[<a name="id26 23571" href="#ftn.id2623571" class="footnote">5</a>]</sup>515 <sup>[<a name="id2617485" href="#ftn.id2617485" class="footnote">5</a>]</sup> 516 516 </p><p> 517 517 If you are using a Windows NT family workstation in place of a server, you must also … … 531 531 The location of the client registry entry for oplocks has changed in 532 532 Windows 2000 from the earlier location in Microsoft Windows NT. 533 </p><div class="note" title="Note"style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>533 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 534 534 Windows 2000 will still respect the EnableOplocks registry value used to disable oplocks 535 535 in earlier versions of Windows. … … 544 544 Default: 0 (not disabled) 545 545 </pre><p> 546 </p><div class="note" title="Note"style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>546 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 547 547 The OplocksDisabled registry value configures Windows clients to either request or not 548 548 request oplocks on a remote file. To disable oplocks, the value of … … 559 559 Default: 0 (Disabled by Default) 560 560 </pre><p> 561 </p><div class="note" title="Note"style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>561 </p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p> 562 562 The EnableOplocks value configures Windows-based servers (including Workstations sharing 563 563 files) to allow or deny oplocks on local files. … … 566 566 </p><p> 567 567 An illustration of how Level2 oplocks work follows: 568 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>568 </p><div class="itemizedlist"><ul type="disc"><li><p> 569 569 Station 1 opens the file requesting oplock. 570 </p></li><li class="listitem"><p>570 </p></li><li><p> 571 571 Since no other station has the file open, the server grants station 1 exclusive oplock. 572 </p></li><li class="listitem"><p>572 </p></li><li><p> 573 573 Station 2 opens the file requesting oplock. 574 </p></li><li class="listitem"><p>574 </p></li><li><p> 575 575 Since station 1 has not yet written to the file, the server asks station 1 to break 576 576 to Level2 oplock. 577 </p></li><li class="listitem"><p>577 </p></li><li><p> 578 578 Station 1 complies by flushing locally buffered lock information to the server. 579 </p></li><li class="listitem"><p>579 </p></li><li><p> 580 580 Station 1 informs the server that it has broken to level2 Oplock (alternately, 581 581 station 1 could have closed the file). 582 </p></li><li class="listitem"><p>582 </p></li><li><p> 583 583 The server responds to station 2's open request, granting it Level2 oplock. 584 584 Other stations can likewise open the file and obtain Level2 oplock. 585 </p></li><li class="listitem"><p>585 </p></li><li><p> 586 586 Station 2 (or any station that has the file open) sends a write request SMB. 587 587 The server returns the write response. 588 </p></li><li class="listitem"><p>588 </p></li><li><p> 589 589 The server asks all stations that have the file open to break to none, meaning no 590 590 station holds any oplock on the file. Because the workstations can have no cached 591 591 writes or locks at this point, they need not respond to the break-to-none advisory; 592 592 all they need do is invalidate locally cashed read-ahead data. 593 </p></li></ul></div><div class="sect2" title="Workstation Service Entries"><div class="titlepage"><div><div><h3 class="title"><a name="id2623726"></a>Workstation Service Entries</h3></div></div></div><pre class="programlisting">593 </p></li></ul></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2617640"></a>Workstation Service Entries</h3></div></div></div><pre class="programlisting"> 594 594 \HKEY_LOCAL_MACHINE\System\ 595 595 CurrentControlSet\Services\LanmanWorkstation\Parameters … … 600 600 This indicates whether the redirector should use oplocks performance 601 601 enhancement. This parameter should be disabled only to isolate problems. 602 </p></div><div class="sect2" title="Server Service Entries"><div class="titlepage"><div><div><h3 class="title"><a name="id2623748"></a>Server Service Entries</h3></div></div></div><pre class="programlisting">602 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2617662"></a>Server Service Entries</h3></div></div></div><pre class="programlisting"> 603 603 \HKEY_LOCAL_MACHINE\System\ 604 604 CurrentControlSet\Services\LanmanServer\Parameters … … 629 629 request. Smaller values can allow detection of crashed clients more quickly but can 630 630 potentially cause loss of cached data. 631 </p></div></div><div class="sect1" title="Persistent Data Corruption"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2623814"></a>Persistent Data Corruption</h2></div></div></div><p>631 </p></div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2617728"></a>Persistent Data Corruption</h2></div></div></div><p> 632 632 If you have applied all of the settings discussed in this chapter but data corruption problems 633 633 and other symptoms persist, here are some additional things to check out. … … 640 640 to the new one. There are several known methods for doing this that can be found in 641 641 our knowledge base. 642 </p></div><div class="sect1" title="Common Errors"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2623839"></a>Common Errors</h2></div></div></div><p>642 </p></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2617754"></a>Common Errors</h2></div></div></div><p> 643 643 In some sites locking problems surface as soon as a server is installed; in other sites 644 644 locking problems may not surface for a long time. Almost without exception, when a locking … … 648 648 that have claimed that Samba caused data corruption. Three causes have been identified 649 649 so far: 650 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>650 </p><div class="itemizedlist"><ul type="disc"><li><p> 651 651 Incorrect configuration of oplocks (incompatible with the application 652 652 being used). This is a common problem even where MS Windows NT4 or MS Windows … … 655 655 disable oplocks on both the server and the client. Disabling of all forms of file 656 656 caching on the MS Windows client may be necessary also. 657 </p></li><li class="listitem"><p>657 </p></li><li><p> 658 658 Defective network cards, cables, or hubs/switches. This is generally a more 659 659 prevalent factor with low-cost networking hardware, although occasionally there 660 660 have also been problems with incompatibilities in more up-market hardware. 661 </p></li><li class="listitem"><p>661 </p></li><li><p> 662 662 There have been some random reports of Samba log files being written over data 663 663 files. This has been reported by very few sites (about five in the past 3 years) … … 670 670 Make sure that you give as much information as you possibly can to help isolate the 671 671 cause and to allow replication of the problem (an essential step in problem isolation and correction). 672 </p></li></ul></div><div class="sect2" title="locking.tdb Error Messages"><div class="titlepage"><div><div><h3 class="title"><a name="id2623907"></a>locking.tdb Error Messages</h3></div></div></div><p>673 <span class="quote">“<span class="quote">672 </p></li></ul></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2617821"></a>locking.tdb Error Messages</h3></div></div></div><p> 673 “<span class="quote"> 674 674 We are seeing lots of errors in the Samba logs, like: 675 </span>” </span>675 </span>” 676 676 </p><pre class="programlisting"> 677 677 tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic … … 679 679 </pre><p> 680 680 681 <span class="quote">“<span class="quote">681 “<span class="quote"> 682 682 What do these mean? 683 </span>” </span>683 </span>” 684 684 </p><p> 685 685 This error indicates a corrupted tdb. Stop all instances of smbd, delete locking.tdb, and restart smbd. 686 </p></div><div class="sect2" title="Problems Saving Files in MS Office on Windows XP"><div class="titlepage"><div><div><h3 class="title"><a name="id2623937"></a>Problems Saving Files in MS Office on Windows XP</h3></div></div></div><a class="indexterm" name="id2623944"></a><p>This is a bug in Windows XP. More information can be686 </p></div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2617852"></a>Problems Saving Files in MS Office on Windows XP</h3></div></div></div><a class="indexterm" name="id2617858"></a><p>This is a bug in Windows XP. More information can be 687 687 found in <a class="ulink" href="http://support.microsoft.com/?id=812937" target="_top">Microsoft Knowledge Base article 812937</a></p>. 688 688 689 </div><div class="sect2" title="Long Delays Deleting Files over Network with XP SP1"><div class="titlepage"><div><div><h3 class="title"><a name="id2623962"></a>Long Delays Deleting Files over Network with XP SP1</h3></div></div></div><p><span class="quote">“<span class="quote">It sometimes takes approximately 35 seconds to delete files over the network after XP SP1 has been applied.</span>”</span></p><a class="indexterm" name="id2623974"></a><p>This is a bug in Windows XP. More information can be found in <a class="ulink" href="http://support.microsoft.com/?id=811492" target="_top">689 </div><div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2617876"></a>Long Delays Deleting Files over Network with XP SP1</h3></div></div></div><p>“<span class="quote">It sometimes takes approximately 35 seconds to delete files over the network after XP SP1 has been applied.</span>”</p><a class="indexterm" name="id2617888"></a><p>This is a bug in Windows XP. More information can be found in <a class="ulink" href="http://support.microsoft.com/?id=811492" target="_top"> 690 690 Microsoft Knowledge Base article 811492</a></p>. 691 </div></div><div class="sect1" title="Additional Reading"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2623993"></a>Additional Reading</h2></div></div></div><p>691 </div></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2617908"></a>Additional Reading</h2></div></div></div><p> 692 692 You may want to check for an updated documentation regarding file and record locking issues on the Microsoft 693 693 <a class="ulink" href="http://support.microsoft.com/" target="_top">Support</a> web site. Additionally, search for the word … … 696 696 Section of the Microsoft MSDN Library on opportunistic locking: 697 697 </p><p> 698 <a class="indexterm" name="id26 24030"></a>699 Microsoft Knowledge Base, <span class="quote">“<span class="quote">Maintaining Transactional Integrity with OPLOCKS</span>”</span>,698 <a class="indexterm" name="id2617944"></a> 699 Microsoft Knowledge Base, “<span class="quote">Maintaining Transactional Integrity with OPLOCKS</span>”, 700 700 Microsoft Corporation, April 1999, <a class="ulink" href="http://support.microsoft.com/?id=224992" target="_top">Microsoft 701 701 KB Article 224992</a>. 702 702 </p><p> 703 <a class="indexterm" name="id26 24054"></a>704 Microsoft Knowledge Base, <span class="quote">“<span class="quote">Configuring Opportunistic Locking in Windows 2000</span>”</span>,703 <a class="indexterm" name="id2617968"></a> 704 Microsoft Knowledge Base, “<span class="quote">Configuring Opportunistic Locking in Windows 2000</span>”, 705 705 Microsoft Corporation, April 2001 <a class="ulink" href="http://support.microsoft.com/?id=296264" target="_top">Microsoft KB Article 296264</a>. 706 706 </p><p> 707 <a class="indexterm" name="id26 24078"></a>708 Microsoft Knowledge Base, <span class="quote">“<span class="quote">PC Ext: Explanation of Opportunistic Locking on Windows NT</span>”</span>,707 <a class="indexterm" name="id2617992"></a> 708 Microsoft Knowledge Base, “<span class="quote">PC Ext: Explanation of Opportunistic Locking on Windows NT</span>”, 709 709 Microsoft Corporation, April 1995 <a class="ulink" href="http://support.microsoft.com/?id=129202" target="_top">Microsoft 710 710 KB Article 129202</a>. 711 </p></div><div class="footnotes"><br><hr width="100" align="left"><div class="footnote"><p><sup>[<a name="ftn.id26 23571" href="#id2623571" class="para">5</a>] </sup>Microsoft has documented this in Knowledge Base article 300216.</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="AccessControls.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="optional.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="securing-samba.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 16. File, Directory, and Share Access Controls </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 18. Securing Samba</td></tr></table></div></body></html>711 </p></div><div class="footnotes"><br><hr width="100" align="left"><div class="footnote"><p><sup>[<a name="ftn.id2617485" href="#id2617485" class="para">5</a>] </sup>Microsoft has documented this in Knowledge Base article 300216.</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="AccessControls.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="optional.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="securing-samba.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 16. File, Directory, and Share Access Controls </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 18. Securing Samba</td></tr></table></div></body></html>
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