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_cacheprime.8"> 4 5<refmeta> 6 <refentrytitle>vfs_cacheprime</refentrytitle> 7 <manvolnum>8</manvolnum> 8 <refmiscinfo class="source">Samba</refmiscinfo> 9 <refmiscinfo class="manual">System Administration tools</refmiscinfo> 10 <refmiscinfo class="version">3.5</refmiscinfo> 11</refmeta> 12 13 14<refnamediv> 15 <refname>vfs_cacheprime</refname> 16 <refpurpose>prime the kernel file data cache</refpurpose> 17</refnamediv> 18 19<refsynopsisdiv> 20 <cmdsynopsis> 21 <command>vfs objects = cacheprime</command> 22 </cmdsynopsis> 23</refsynopsisdiv> 24 25<refsect1> 26 <title>DESCRIPTION</title> 27 28 <para>This VFS module is part of the 29 <citerefentry><refentrytitle>samba</refentrytitle> 30 <manvolnum>7</manvolnum></citerefentry> suite.</para> 31 32 <para>The <command>vfs_cacheprime</command> VFS module reads chunks 33 of file data near the range requested by clients in order to 34 make sure the data is present in the kernel file data cache at 35 the time when it is actually requested by clients. </para> 36 37 <para>The size of the disk read operations performed 38 by <command>vfs_cacheprime</command> is determined by the 39 cacheprime:rsize option. All disk read operations are aligned 40 on boundaries that are a multiple of this size. Each range of 41 the file data is primed at most once during the time the client 42 has the file open. </para> 43 44 <para>This module is stackable.</para> 45</refsect1> 46 47<refsect1> 48 <title>OPTIONS</title> 49 50 <variablelist> 51 52 <varlistentry> 53 <term>cacheprime:rsize = BYTES</term> 54 <listitem> 55 <para>The number of bytes with which to prime 56 the kernel data cache.</para> 57 <para>The following suffixes may be applied to BYTES:</para> 58 <itemizedlist> 59 <listitem><para><command>K</command> - BYTES is a number of kilobytes</para></listitem> 60 <listitem><para><command>M</command> - BYTES is a number of megabytes</para></listitem> 61 <listitem><para><command>G</command> - BYTES is a number of gigabytes</para></listitem> 62 </itemizedlist> 63 64 </listitem> 65 </varlistentry> 66 67 </variablelist> 68</refsect1> 69 70<refsect1> 71 <title>EXAMPLES</title> 72 73 <para>For a hypothetical disk array, it is necessary to ensure 74 that all read operations are of size 1 megabyte (1048576 bytes), 75 and aligned on 1 megabyte boundaries: 76 </para> 77<programlisting> 78 <smbconfsection name="[hypothetical]"/> 79 <smbconfoption name="vfs objects">cacheprime</smbconfoption> 80 <smbconfoption name="cacheprime:rsize">1M</smbconfoption> 81</programlisting> 82 83</refsect1> 84 85<refsect1> 86 <title>CAVEATS</title> 87 <para><command>cacheprime</command> is not a a substitute for 88 a general-purpose readahead mechanism. It is intended for use 89 only in very specific environments where disk operations must 90 be aligned and sized to known values (as much as that is possible). 91 </para> 92</refsect1> 93 94<refsect1> 95 <title>VERSION</title> 96 <para>This man page is correct for version 3.0.25 of the Samba suite. 97 </para> 98</refsect1> 99 100<refsect1> 101 <title>AUTHOR</title> 102 103 <para>The original Samba software and related utilities 104 were created by Andrew Tridgell. Samba is now developed 105 by the Samba Team as an Open Source project similar 106 to the way the Linux kernel is developed.</para> 107 108</refsect1> 109 110</refentry> 111