| 1 | '\" t
|
|---|
| 2 | .\" Title: vfs_preopen
|
|---|
| 3 | .\" Author: [see the "AUTHOR" section]
|
|---|
| 4 | .\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
|
|---|
| 5 | .\" Date: 10/25/2016
|
|---|
| 6 | .\" Manual: System Administration tools
|
|---|
| 7 | .\" Source: Samba 4.4
|
|---|
| 8 | .\" Language: English
|
|---|
| 9 | .\"
|
|---|
| 10 | .TH "VFS_PREOPEN" "8" "10/25/2016" "Samba 4\&.4" "System Administration tools"
|
|---|
| 11 | .\" -----------------------------------------------------------------
|
|---|
| 12 | .\" * Define some portability stuff
|
|---|
| 13 | .\" -----------------------------------------------------------------
|
|---|
| 14 | .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|---|
| 15 | .\" http://bugs.debian.org/507673
|
|---|
| 16 | .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
|
|---|
| 17 | .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|---|
| 18 | .ie \n(.g .ds Aq \(aq
|
|---|
| 19 | .el .ds Aq '
|
|---|
| 20 | .\" -----------------------------------------------------------------
|
|---|
| 21 | .\" * set default formatting
|
|---|
| 22 | .\" -----------------------------------------------------------------
|
|---|
| 23 | .\" disable hyphenation
|
|---|
| 24 | .nh
|
|---|
| 25 | .\" disable justification (adjust text to left margin only)
|
|---|
| 26 | .ad l
|
|---|
| 27 | .\" -----------------------------------------------------------------
|
|---|
| 28 | .\" * MAIN CONTENT STARTS HERE *
|
|---|
| 29 | .\" -----------------------------------------------------------------
|
|---|
| 30 | .SH "NAME"
|
|---|
| 31 | vfs_preopen \- Hide read latencies for applications reading numbered files
|
|---|
| 32 | .SH "SYNOPSIS"
|
|---|
| 33 | .HP \w'\ 'u
|
|---|
| 34 | vfs objects = preopen
|
|---|
| 35 | .SH "DESCRIPTION"
|
|---|
| 36 | .PP
|
|---|
| 37 | This VFS module is part of the
|
|---|
| 38 | \fBsamba\fR(7)
|
|---|
| 39 | suite\&.
|
|---|
| 40 | .PP
|
|---|
| 41 | This module assists applications that want to read numbered files in sequence with very strict latency requirements\&. One area where this happens in video streaming applications that want to read one file per frame\&.
|
|---|
| 42 | .PP
|
|---|
| 43 | When you use this module, a number of helper processes is started that speculatively open files and read a number of bytes to prime the file system cache, so that later on when the real application\*(Aqs request comes along, no disk access is necessary\&.
|
|---|
| 44 | .PP
|
|---|
| 45 | This module is stackable\&.
|
|---|
| 46 | .SH "OPTIONS"
|
|---|
| 47 | .PP
|
|---|
| 48 | preopen:names = /pattern/
|
|---|
| 49 | .RS 4
|
|---|
| 50 | preopen:names specifies the file name pattern which should trigger the preopen helpers to do their work\&. We assume that the files are numbered incrementally\&. So if your file names are numbered FRAME00000\&.frm FRAME00001\&.frm and so on you would list them as
|
|---|
| 51 | preopen:names=/FRAME*\&.frm/
|
|---|
| 52 | .RE
|
|---|
| 53 | .PP
|
|---|
| 54 | preopen:num_bytes = BYTES
|
|---|
| 55 | .RS 4
|
|---|
| 56 | Specifies the number of bytes the helpers should speculatively read, defaults to 1\&.
|
|---|
| 57 | .RE
|
|---|
| 58 | .PP
|
|---|
| 59 | preopen:helpers = NUM\-PROCS
|
|---|
| 60 | .RS 4
|
|---|
| 61 | Number of forked helper processes, defaults to 1\&.
|
|---|
| 62 | .RE
|
|---|
| 63 | .PP
|
|---|
| 64 | preopen:queuelen = NUM\-FILES
|
|---|
| 65 | .RS 4
|
|---|
| 66 | Number of files that should be speculatively opened\&. Defaults to the 10 subsequent files\&.
|
|---|
| 67 | .RE
|
|---|
| 68 | .SH "VERSION"
|
|---|
| 69 | .PP
|
|---|
| 70 | This man page is correct for version 3\&.3 of the Samba suite\&.
|
|---|
| 71 | .SH "AUTHOR"
|
|---|
| 72 | .PP
|
|---|
| 73 | The original Samba software and related utilities were created by Andrew Tridgell\&. Samba is now developed by the Samba Team as an Open Source project similar to the way the Linux kernel is developed\&.
|
|---|
| 74 | .PP
|
|---|
| 75 | The PREOPEN VFS module was created with contributions from Volker Lendecke and the developers at IBM\&.
|
|---|
