From 010f2b89e20e13f4687700fd731fedfafb7c62eb Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 17 Apr 2012 20:20:28 -0700 Subject: Add docs for aio_linux vfs module. Autobuild-User: Jeremy Allison Autobuild-Date: Wed Apr 18 07:20:19 CEST 2012 on sn-devel-104 --- docs-xml/manpages-3/vfs_aio_linux.8.xml | 115 ++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 docs-xml/manpages-3/vfs_aio_linux.8.xml (limited to 'docs-xml') diff --git a/docs-xml/manpages-3/vfs_aio_linux.8.xml b/docs-xml/manpages-3/vfs_aio_linux.8.xml new file mode 100644 index 0000000000..dac94a5794 --- /dev/null +++ b/docs-xml/manpages-3/vfs_aio_linux.8.xml @@ -0,0 +1,115 @@ + + + + + + vfs_aio_linux + 8 + Samba + System Administration tools + 3.6 + + + + + vfs_aio_linux + implement async I/O in Samba vfs using Linux kernel aio calls + + + + + vfs objects = aio_linux + + + + + DESCRIPTION + + This VFS module is part of the + samba + 7 suite. + + The aio_linux VFS module enables asynchronous + I/O for Samba on Linux kernels that have the kernel AIO calls available + without using the Posix AIO interface. 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 which essentially makes Posix AIO useless on systems + using the glibc implementation. + + To work around all these limitations, the aio_linux module + was written. It uses the Linux kernel AIO interface instead of the + internal Posix AIO interface to allow read and write calls + to be processed asynchronously. A queue size of 128 events + is used by default. To change this limit set the "aio num events" + parameter below. + + + + Note that the smb.conf parameters aio read size + and aio write size must also be set appropriately + for this module to be active. + + + This module MUST be listed last in any module stack as + the Samba VFS pread/pwrite interface is not thread-safe. This + module makes direct pread and pwrite system calls and does + NOT call the Samba VFS pread and pwrite interfaces. + + + + + + EXAMPLES + + Straight forward use: + + + + /data/ice + 1024 + 1024 + aio_linux + + + + + + OPTIONS + + + + + aio_linux:aio num events = INTEGER + + Set the maximum size of the event queue + that is used to limit outstanding IO requests. + + By default this is set to 128. + + + + + + + VERSION + + This man page is correct for version 3.6.6 of the Samba suite. + + + + + AUTHOR + + 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. + + + + -- cgit