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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_aio_fork.8">
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<refentrytitle>vfs_aio_fork</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">3.6</refmiscinfo>
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<refname>vfs_aio_fork</refname>
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<refpurpose>implement async I/O in Samba vfs</refpurpose>
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<command>vfs objects = aio_fork</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>aio_fork</command> VFS module enables async
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I/O for Samba on platforms where the system level Posix AIO
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interface is insufficient. Posix AIO can suffer from severe
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limitations. For example, on some Linux versions the
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real-time signals that it uses are broken under heavy load.
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Other systems only allow AIO when special kernel modules are
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loaded or only allow a certain system-wide amount of async
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requests being scheduled. Systems based on glibc (most Linux
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systems) only allow a single outstanding request per file
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<para>To work around all these limitations, the aio_fork module
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was written. It uses forked helper processes instead of the
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internal Posix AIO interface to create asynchronousity for
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read and write calls. It has no parameters, it will create
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helper processes when async requests come in as needed. Idle
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helper processes will be removed every 30 seconds.
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<para>This module is stackable.</para>
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<title>EXAMPLES</title>
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<para>Straight forward use:</para>
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<smbconfsection name="[cooldata]"/>
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<smbconfoption name="path">/data/ice</smbconfoption>
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<smbconfoption name="vfs objects">aio_fork</smbconfoption>
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<title>VERSION</title>
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<para>This man page is correct for version 3.6.0 of the Samba suite.
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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>