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diff --git a/docs-xml/manpages/vfs_preopen.8.xml b/docs-xml/manpages/vfs_preopen.8.xml new file mode 100644 index 0000000..e826d72 --- /dev/null +++ b/docs-xml/manpages/vfs_preopen.8.xml @@ -0,0 +1,275 @@ +<?xml version="1.0" encoding="iso-8859-1"?> +<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc"> +<refentry id="vfs_preopen.8"> + +<refmeta> + <refentrytitle>vfs_preopen</refentrytitle> + <manvolnum>8</manvolnum> + <refmiscinfo class="source">Samba</refmiscinfo> + <refmiscinfo class="manual">System Administration tools</refmiscinfo> + <refmiscinfo class="version">&doc.version;</refmiscinfo> +</refmeta> + +<refnamediv> + <refname>vfs_preopen</refname> + <refpurpose>Hide read latencies for applications reading numbered files</refpurpose> +</refnamediv> + +<refsynopsisdiv> + <cmdsynopsis> + <command>vfs objects = preopen</command> + </cmdsynopsis> +</refsynopsisdiv> + +<refsect1> + <title>DESCRIPTION</title> + + <para>This VFS module is part of the + <citerefentry><refentrytitle>samba</refentrytitle> + <manvolnum>7</manvolnum></citerefentry> suite.</para> + + <para>This module assists applications that want to read numbered + files in sequence with very strict latency requirements. One area + where this happens in video streaming applications that want to read + one file per frame.</para> + + <para>When you use this module, a number of helper processes is + started that speculatively open files and read a number of bytes to + prime the file system cache, so that later on when the real + application's request comes along, no disk access is necessary.</para> + + <para>This module is stackable.</para> + +</refsect1> + + +<refsect1> + <title>OPTIONS</title> + + <variablelist> + + <varlistentry> + <term>preopen:posix-basic-regex = BOOL (default: no)</term> + <listitem> + <para> + <command>preopen:posix-basic-regex = yes</command> changes + the meaning of the <command>preopen:names</command> option. + Further details are described there. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:names = /pattern1/pattern2/</term> + <listitem> + <para> + preopen:names specifies the file name pattern(s) which should + trigger the preopen helpers to do their work. We assume that + the files are numbered incrementally. So if your file names + are numbered FRAME00000.frm FRAME00001.frm and so on you would + list them as <command>preopen:names=/FRAME*.frm/</command>. + The default algorithm uses the first (at least 3) digits it finds + in order to calculate the name of the next frames. + </para> + + <para><command>preopen:posix-basic-regex = yes</command> changes + the meaning of the <command>preopen:names</command> option. + It means 'POSIX Basic Regular Expression' strings are used + as patterns. The key is each pattern requires exactly one + 'subexpression' starting with '\(' and ending with '\)' in + order to specify the position of the digits representing + the incrementing frame numbers. Given a file names like + Movie7599Frame0v1234.txt, Movie7599Frame1v1234.txt, Movie7599Frame2v1234.txt + up to Movie7599Frame9v1234.txt you can use <command>preopen:names = /.*Frame\([0-9]\).*\.txt/</command> + in order to match just a single digits, this might not be a real world example, + but it shows the flexiblity that is possible here. + </para> + + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:num_bytes = BYTES</term> + <listitem> + <para> + Specifies the number of bytes the helpers should speculatively + read, defaults to 1. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:helpers = NUM-PROCS</term> + <listitem> + <para> + Number of forked helper processes, defaults to 1. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:queuelen = NUM-FILES</term> + <listitem> + <para> + Number of files that should be speculatively opened. Defaults + to the 10 subsequent files. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:nomatch_log_level = LOGLEVEL</term> + <listitem> + <para> + In order to debug or audit the usage of the preopen logic + you can use this option to specify at what log level details + about filenames not matching any pattern from '<command>preopen:names</command>' + are logged. + </para> + <para> + Defaults to the log level 5. + See also <citerefentry><refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + in the '<smbconfoption name="log level"/>' section + for special handling of the 'preopen' debug class. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:match_log_level = LOGLEVEL</term> + <listitem> + <para> + In order to debug or audit the usage of the preopen logic + you can use this option to specify at what log level details + about filenames actually matching a pattern from '<command>preopen:names</command>' + are logged. + </para> + <para> + See also '<command>preopen:founddigits_log_level</command>' and '<command>preopen:push_log_level</command>'. + </para> + <para> + Defaults to the log level 5. + See also <citerefentry><refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + in the '<smbconfoption name="log level"/>' section + for special handling of the 'preopen' debug class. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:nodigits_log_level = LOGLEVEL</term> + <listitem> + <para> + In order to debug or audit problems with the preopen configuration + you can use this option to specify at what log level details + about filenames actually matching a pattern from '<command>preopen:names</command>', + but at the same time don't contain the expected digits, are logged. + This is typically something the administrator wants to notice and + adjust the configuration in order to define more precisely where to + find the digits in the filename. + </para> + <para> + Defaults to the log level 1. + See also <citerefentry><refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + in the '<smbconfoption name="log level"/>' section + for special handling of the 'preopen' debug class. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:founddigits_log_level = LOGLEVEL</term> + <listitem> + <para> + In order to debug or audit the usage of the preopen logic + you can use this option to specify at what log level details + about filenames actually matching a pattern from '<command>preopen:names</command>', + and at the same time having valid expected digits, are logged. This means enough information is available + in order to queue preopens. + </para> + <para> + Defaults to the log level 3. + See also <citerefentry><refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + in the '<smbconfoption name="log level"/>' section + for special handling of the 'preopen' debug class. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:reset_log_level = LOGLEVEL</term> + <listitem> + <para> + If a matching filename belongs to a different pattern from '<command>preopen:names</command>', + a different parent directory or differs in a significant way from the last filename + that was found before, the module needs to reset it's internal queue state. + This means that no more preopens will be pushed to helper processes belonging to the + former queue state. In order to debug or audit such queue resets you can use this option to specify at what + log level details are logged. + </para> + <para> + Defaults to the log level 5. + See also <citerefentry><refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + in the '<smbconfoption name="log level"/>' section + for special handling of the 'preopen' debug class. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:push_log_level = LOGLEVEL</term> + <listitem> + <para> + In order to debug or audit the usage of the preopen logic + you can use this option to specify at what log level details + about filenames actually pushed to preopen helper processes are logged. + This means they will actually be preopened soon. + </para> + <para> + Defaults to the log level 3. + See also <citerefentry><refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + in the '<smbconfoption name="log level"/>' section + for special handling of the 'preopen' debug class. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term>preopen:queue_log_level = LOGLEVEL</term> + <listitem> + <para> + In order to debug details about internal queue processing + you can use this option to specify at what log level the details are logged. + </para> + <para> + Defaults to the log level 10. + See also <citerefentry><refentrytitle>smb.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + in the '<smbconfoption name="log level"/>' section + for special handling of the 'preopen' debug class. + </para> + </listitem> + </varlistentry> + + </variablelist> +</refsect1> + +<refsect1> + <title>VERSION</title> + <para>This man page is part of version &doc.version; of the Samba suite. + </para> +</refsect1> + +<refsect1> + <title>AUTHOR</title> + + <para>The original Samba software and related utilities + were created by Andrew Tridgell. Samba is now developed + by the Samba Team as an Open Source project similar + to the way the Linux kernel is developed.</para> + + <para>The PREOPEN VFS module was created with contributions from + Volker Lendecke and the developers at IBM. + </para> +</refsect1> + +</refentry> |