| 1 | <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>vfs_cacheprime</title><link rel="stylesheet" href="samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.71.0"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" lang="en"><a name="vfs_cacheprime.8"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>vfs_cacheprime — prime the kernel file data cache</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">vfs objects = cacheprime</code> </p></div></div><div class="refsect1" lang="en"><a name="id291819"></a><h2>DESCRIPTION</h2><p>This VFS module is part of the |
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| 2 | <a href="samba.7.html"><span class="citerefentry"><span class="refentrytitle">samba</span>(7)</span></a> suite.</p><p>The <span><strong class="command">vfs_cacheprime</strong></span> VFS module reads chunks |
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| 3 | of file data near the range requested by clients in order to |
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| 4 | make sure the data is present in the kernel file data cache at |
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| 5 | the time when it is actually requested by clients. </p><p>The size of the disk read operations performed |
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| 6 | by <span><strong class="command">vfs_cacheprime</strong></span> is determined by the |
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| 7 | cacheprime:rsize option. All disk read operations are aligned |
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| 8 | on boundaries that are a multiple of this size. Each range of |
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| 9 | the file data is primed at most once during the time the client |
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| 10 | has the file open. </p><p>This module is stackable.</p></div><div class="refsect1" lang="en"><a name="id259549"></a><h2>OPTIONS</h2><div class="variablelist"><dl><dt><span class="term">cacheprime:rsize = BYTES</span></dt><dd><p>The number of bytes with which to prime |
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| 11 | the kernel data cache.</p><p>The following suffixes may be applied to BYTES:</p><div class="itemizedlist"><ul type="disc"><li><p><span><strong class="command">K</strong></span> - BYTES is a number of kilobytes</p></li><li><p><span><strong class="command">M</strong></span> - BYTES is a number of megabytes</p></li><li><p><span><strong class="command">G</strong></span> - BYTES is a number of gigabytes</p></li></ul></div></dd></dl></div></div><div class="refsect1" lang="en"><a name="id259606"></a><h2>EXAMPLES</h2><p>For a hypothetical disk array, it is necessary to ensure |
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| 12 | that all read operations are of size 1 megabyte (1048576 bytes), |
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| 13 | and aligned on 1 megabyte boundaries: |
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| 14 | </p><pre class="programlisting"> |
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| 15 | <em class="parameter"><code>[hypothetical]</code></em> |
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| 16 | <a class="indexterm" name="id259376"></a>vfs objects = cacheprime |
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| 17 | <a class="indexterm" name="id259384"></a>cacheprime:rsize = 1M |
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| 18 | </pre></div><div class="refsect1" lang="en"><a name="id259393"></a><h2>CAVEATS</h2><p><span><strong class="command">cacheprime</strong></span> is not a a substitute for |
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| 19 | a general-purpose readahead mechanism. It is intended for use |
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| 20 | only in very specific environments where disk operations must |
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| 21 | be aligned and sized to known values (as much as that is possible). |
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| 22 | </p></div><div class="refsect1" lang="en"><a name="id259409"></a><h2>VERSION</h2><p>This man page is correct for version 3.0.25 of the Samba suite. |
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| 23 | </p></div><div class="refsect1" lang="en"><a name="id259419"></a><h2>AUTHOR</h2><p>The original Samba software and related utilities |
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| 24 | were created by Andrew Tridgell. Samba is now developed |
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| 25 | by the Samba Team as an Open Source project similar |
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| 26 | to the way the Linux kernel is developed.</p></div></div></body></html> |
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