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<?xml version="1.0" encoding="iso-8859-1"?>
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<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
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<refentry id="vfs_cacheprime.8">
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<refentrytitle>vfs_cacheprime</refentrytitle>
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<manvolnum>8</manvolnum>
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<refmiscinfo class="source">Samba</refmiscinfo>
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<refmiscinfo class="manual">System Administration tools</refmiscinfo>
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<refmiscinfo class="version">3.4</refmiscinfo>
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<refname>vfs_cacheprime</refname>
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<refpurpose>prime the kernel file data cache</refpurpose>
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<command>vfs objects = cacheprime</command>
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<title>DESCRIPTION</title>
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<para>This VFS module is part of the
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<citerefentry><refentrytitle>samba</refentrytitle>
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<manvolnum>7</manvolnum></citerefentry> suite.</para>
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<para>The <command>vfs_cacheprime</command> VFS module reads chunks
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of file data near the range requested by clients in order to
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make sure the data is present in the kernel file data cache at
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the time when it is actually requested by clients. </para>
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<para>The size of the disk read operations performed
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by <command>vfs_cacheprime</command> is determined by the
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cacheprime:rsize option. All disk read operations are aligned
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on boundaries that are a multiple of this size. Each range of
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the file data is primed at most once during the time the client
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has the file open. </para>
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<para>This module is stackable.</para>
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<title>OPTIONS</title>
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<term>cacheprime:rsize = BYTES</term>
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<para>The number of bytes with which to prime
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the kernel data cache.</para>
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<para>The following suffixes may be applied to BYTES:</para>
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<listitem><para><command>K</command> - BYTES is a number of kilobytes</para></listitem>
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<listitem><para><command>M</command> - BYTES is a number of megabytes</para></listitem>
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<listitem><para><command>G</command> - BYTES is a number of gigabytes</para></listitem>
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<title>EXAMPLES</title>
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<para>For a hypothetical disk array, it is necessary to ensure
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that all read operations are of size 1 megabyte (1048576 bytes),
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and aligned on 1 megabyte boundaries:
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<smbconfsection name="[hypothetical]"/>
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<smbconfoption name="vfs objects">cacheprime</smbconfoption>
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<smbconfoption name="cacheprime:rsize">1M</smbconfoption>
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<title>CAVEATS</title>
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<para><command>cacheprime</command> is not a a substitute for
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a general-purpose readahead mechanism. It is intended for use
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only in very specific environments where disk operations must
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be aligned and sized to known values (as much as that is possible).
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<title>VERSION</title>
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<para>This man page is correct for version 3.0.25 of the Samba suite.
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<title>AUTHOR</title>
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<para>The original Samba software and related utilities
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were created by Andrew Tridgell. Samba is now developed
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by the Samba Team as an Open Source project similar
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to the way the Linux kernel is developed.</para>