| 1 | @c This is part of the paxutils manual.
|
|---|
| 2 | @c Copyright (C) 2005 Free Software Foundation, Inc.
|
|---|
| 3 | @c Written by Sergey Poznyakoff
|
|---|
| 4 | @c This file is distributed under GFDL 1.1 or any later version
|
|---|
| 5 | @c published by the Free Software Foundation.
|
|---|
| 6 |
|
|---|
| 7 | A @dfn{snapshot file} (or @dfn{directory file}) is created during
|
|---|
| 8 | incremental backups (@pxref{Incremental Dumps}). It
|
|---|
| 9 | contains the status of the file system at the time of the dump and is
|
|---|
| 10 | used to determine which files were modified since the last backup.
|
|---|
| 11 |
|
|---|
| 12 | @GNUTAR{} version @value{VERSION} supports two snapshot file
|
|---|
| 13 | formats. The first format, called @dfn{format 0}, is the one used by
|
|---|
| 14 | @GNUTAR{} versions up to 1.15.1. The second format, called @dfn{format
|
|---|
| 15 | 1} is an extended version of this format, that contains more metadata
|
|---|
| 16 | and allows for further extensions.
|
|---|
| 17 |
|
|---|
| 18 | @samp{Format 0} snapshot file begins with a line containing a
|
|---|
| 19 | decimal number that represents the UNIX timestamp of the beginning of
|
|---|
| 20 | the last archivation. This line is followed by directory metadata
|
|---|
| 21 | descriptions, one per line. Each description has the following format:
|
|---|
| 22 |
|
|---|
| 23 | @smallexample
|
|---|
| 24 | [@var{nfs}]@var{dev} @var{inode} @var{name}
|
|---|
| 25 | @end smallexample
|
|---|
| 26 |
|
|---|
| 27 | @noindent
|
|---|
| 28 | where optional @var{nfs} is a single plus character (@samp{+}) if this
|
|---|
| 29 | directory is located on an NFS-mounted partition, @var{dev} and
|
|---|
| 30 | @var{inode} are the device and inode numbers of the directory, and
|
|---|
| 31 | @var{name} is the directory name.
|
|---|
| 32 |
|
|---|
| 33 | @samp{Format 1} snapshot file begins with a line specifying the
|
|---|
| 34 | format of the file. This line has the following structure:
|
|---|
| 35 |
|
|---|
| 36 | @smallexample
|
|---|
| 37 | @samp{GNU tar-}@var{tar-version}@samp{-}@var{incr-format-version}
|
|---|
| 38 | @end smallexample
|
|---|
| 39 |
|
|---|
| 40 | @noindent
|
|---|
| 41 | where @var{tar-version} is the version of @GNUTAR{} implementation
|
|---|
| 42 | that created this snapshot, and @var{incr-format-version} is the
|
|---|
| 43 | version number of the snapshot format (in this case @samp{1}).
|
|---|
| 44 |
|
|---|
| 45 | The following line contains two decimal numbers, representing the
|
|---|
| 46 | time of the last backup. First number is the number of seconds, the
|
|---|
| 47 | second one is the number of nanoseconds, since the beginning of the
|
|---|
| 48 | epoch.
|
|---|
| 49 |
|
|---|
| 50 | Following lines contain directory metadata, one line per
|
|---|
| 51 | directory. The line format is:
|
|---|
| 52 |
|
|---|
| 53 | @smallexample
|
|---|
| 54 | [@var{nfs}]@var{mtime-sec} @var{mtime-nsec} @var{dev} @var{inode} @var{name}
|
|---|
| 55 | @end smallexample
|
|---|
| 56 |
|
|---|
| 57 | @noindent
|
|---|
| 58 | where @var{mtime-sec} and @var{mtime-nsec} represent the last
|
|---|
| 59 | modification time of this directory with nanosecond precision;
|
|---|
| 60 | @var{nfs}, @var{dev}, @var{inode} and @var{name} have the same meaning
|
|---|
| 61 | as with @samp{format 0}.
|
|---|
| 62 |
|
|---|
| 63 |
|
|---|
| 64 | @c End of snapshot.texi
|
|---|
| 65 |
|
|---|
| 66 |
|
|---|
