'\" t
.\"     Title: vfs_aio_fork
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: 02/21/2015
.\"    Manual: System Administration tools
.\"    Source: Samba 4.0
.\"  Language: English
.\"
.TH "VFS_AIO_FORK" "8" "02/21/2015" "Samba 4\&.0" "System Administration tools"
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.SH "NAME"
vfs_aio_fork \- implement async I/O in Samba vfs
.SH "SYNOPSIS"
.HP \w'\ 'u
vfs objects = aio_fork
.SH "DESCRIPTION"
.PP
This VFS module is part of the
\fBsamba\fR(7)
suite\&.
.PP
The
aio_fork
VFS module enables async I/O for Samba on platforms where the system level Posix AIO interface is insufficient\&. Posix AIO can suffer from severe limitations\&. For example, on some Linux versions the real\-time signals that it uses are broken under heavy load\&. Other systems only allow AIO when special kernel modules are loaded or only allow a certain system\-wide amount of async requests being scheduled\&. Systems based on glibc (most Linux systems) only allow a single outstanding request per file descriptor\&.
.PP
To work around all these limitations, the aio_fork module was written\&. It uses forked helper processes instead of the internal Posix AIO interface to create asynchronousity for read and write calls\&. It has no parameters, it will create helper processes when async requests come in as needed\&. Idle helper processes will be removed every 30 seconds\&.
.PP
This module is stackable\&.
.SH "EXAMPLES"
.PP
Straight forward use:
.sp
.if n \{\
.RS 4
.\}
.nf
        \fI[cooldata]\fR
	\m[blue]\fBpath = /data/ice\fR\m[]
	\m[blue]\fBvfs objects = aio_fork\fR\m[]
.fi
.if n \{\
.RE
.\}
.SH "VERSION"
.PP
This man page is correct for version 4\&.0\&.0 of the Samba suite\&.
.SH "AUTHOR"
.PP
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\&.