manpages-3/vfs_commit.8.xml

   1 <?xml version="1.0" encoding="iso-8859-1"?>
   2 <!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
   3 <refentry id="vfs_commit.8">
   4
   5 <refmeta>
   6         <refentrytitle>vfs_commit</refentrytitle>
   7         <manvolnum>8</manvolnum>
   8 </refmeta>
   9
  10
  11 <refnamediv>
  12         <refname>vfs_commit</refname>
  13         <refpurpose>flush dirty data at specified intervals</refpurpose>
  14 </refnamediv>
  15
  16 <refsynopsisdiv>
  17         <cmdsynopsis>
  18                 <command>vfs objects = commit</command>
  19         </cmdsynopsis>
  20 </refsynopsisdiv>
  21
  22 <refsect1>
  23         <title>DESCRIPTION</title>
  24
  25         <para>This VFS module is part of the
  26         <citerefentry><refentrytitle>samba</refentrytitle>
  27         <manvolnum>7</manvolnum></citerefentry> suite.</para>
  28
  29         <para>The <command>vfs_commit</command> VFS module keeps track of
  30         the amount of data written to a file and synchronizes it to
  31         disk when a specified amount accumulates.
  32         </para>
  33
  34         <para><command>vfs_commit</command> is useful in two
  35         circumstances. First, if you have very precious data, the
  36         impact of unexpected power loss can be minimized by a small
  37         commit:dthresh value. Secondly, write performance can be
  38         improved on some systems by flushing file data early and at
  39         regular intervals.</para>
  40
  41         <para>This module is stackable.</para>
  42
  43 </refsect1>
  44
  45
  46 <refsect1>
  47         <title>OPTIONS</title>
  48
  49         <variablelist>
  50
  51                 <varlistentry>
  52                 <term>commit:dthresh = BYTES</term>
  53                 <listitem>
  54                 <para>Synchronize file data each time the specified
  55                 number of bytes has been written.
  56                 </para>
  57
  58                 <para>The following suffixes may be applied to BYTES:</para>
  59                 <itemizedlist>
  60                 <listitem><para><command>K</command> - BYTES is a number of kilobytes</para></listitem>
  61                 <listitem><para><command>M</command> - BYTES is a number of megabytes</para></listitem>
  62                 <listitem><para><command>G</command> - BYTES is a number of gigabytes</para></listitem>
  63                 </itemizedlist>
  64
  65                 </listitem>
  66                 </varlistentry>
  67
  68         </variablelist>
  69 </refsect1>
  70
  71 <refsect1>
  72         <title>EXAMPLES</title>
  73
  74         <para>Synchronize the file data on the [precious] share after
  75         every 512 kilobytes (524288 bytes) of data is written:</para>
  76 <programlisting>
  77         <smbconfsection name="[precious]"/>
  78         <smbconfoption name="path">/data/precious</smbconfoption>
  79         <smbconfoption name="vfs objects">commit</smbconfoption>
  80         <smbconfoption name="commit:dthresh">512K</smbconfoption>
  81 </programlisting>
  82 </refsect1>
  83
  84 <refsect1>
  85         <title>CAVEATS</title>
  86         <para>On some systems, the data synchronization performed by
  87         <command>commit</command> may reduce performance.
  88         </para>
  89 </refsect1>
  90
  91 <refsect1>
  92         <title>VERSION</title>
  93         <para>This man page is correct for version 3.0.25 of the Samba suite.
  94         </para>
  95 </refsect1>
  96
  97 <refsect1>
  98         <title>AUTHOR</title>
  99
 100         <para>The original Samba software and related utilities
 101         were created by Andrew Tridgell. Samba is now developed
 102         by the Samba Team as an Open Source project similar
 103         to the way the Linux kernel is developed.</para>
 104
 105 </refsect1>
 106
 107 </refentry>