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Making the ZFS snapshot service run faster
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ZFS-FUSE(8) [FIXME: manual] ZFS-FUSE(8) NAME
zfs-fuse - ZFS filesystem daemon SYNOPSIS
zfs-fuse [--pidfile filename] [--no-daemon] [--no-kstat-mount] [--disable-block-cache] [--disable-page-cache] [--fuse-attr-timeout SECONDS] [--fuse-entry-timeout SECONDS] [--log-uberblocks] [--max-arc-size MB] [--fuse-mount-options OPT,OPT,OPT...] [--min-uberblock-txg MIN] [--stack-size=size] [--enable-xattr] [--help] DESCRIPTION
This manual page documents briefly the zfs-fuse command. zfs-fuse is a daemon which provides support for the ZFS filesystem, via fuse. Ordinarily this daemon will be invoked from system boot scripts. OPTIONS
This program follows the usual GNU command line syntax, with long options starting with two dashes (`-'). A summary of options is included below. For a complete description, see the Info files. -h --help Show summary of options. -p filename --pidfile filename Write the daemon's PID to filename after daemonizing. Ignored if --no-daemon is passed. filename should be a fully-qualified path. -n --no-daemon Stay in foreground, don't daemonize. --no-kstat-mount Do not mount kstats in /zfs-kstat --disable-block-cache Enable direct I/O for disk operations. Completely disables caching reads and writes in the kernel block cache. Breaks mmap() in ZFS datasets too. --disable-page-cache Disable the page cache for files residing within ZFS filesystems. Not recommended as it slows down I/O operations considerably. -a SECONDS --fuse-attr-timeout SECONDS Sets timeout for caching FUSE attributes in kernel. Defaults to 0.0. Higher values give a 40% performance boost. -e SECONDS --fuse-entry-timeout SECONDS Sets timeout for caching FUSE entries in kernel. Defaults to 0.0. Higher values give a 10000% performance boost but cause file permission checking security issues. --log-uberblocks Logs uberblocks of any mounted filesystem to syslog -m MB --max-arc-size MB Forces the maximum ARC size (in megabytes). Range: 16 to 16384. -o OPT... --fuse-mount-options OPT,OPT,OPT... Sets FUSE mount options for all filesystems. Format: comma-separated string of characters. -u MIN --min-uberblock-txg MIN Skips uberblocks with a TXG < MIN when mounting any fs -v MB --vdev-cache-size MB adjust the size of the vdev cache. Default : 10 --zfs-prefetch-disable Disable the high level prefetch cache in zfs. This thing can eat up to 150 Mb of ram, maybe more --stack-size=size Limit the stack size of threads (in kb). default : no limit (8 Mb for linux) -x --enable-xattr Enable support for extended attributes. Not generally recommended because it currently has a significant performance penalty for many small IOPS -h --help Show this usage summary. REMARKS ON PRECEDENCE
Note that the parameters passed on the command line take precedence over those supplied through /etc/zfs/zfsrc. BUGS
/CAVEATS The path to the configuration file (/etc/zfs/zfsrc) cannot at this time be configured. Most existing packages suggest settings can be set at the top of their init script. These get frequently overridden by a (distribution specific) /etc/default/zfs-fuse file, if it exists. Be sure to look at these places if you want your changes to options to take effect. The /etc/zfs/zfsrc is going to be the recommended approach in the future. So, packagers, please refrain from passing commandline parameters within the initscript (except for --pid-file). SEE ALSO
zfs (8), zpool (8), zdb(8), zstreamdump(8), /etc/zfs/zfsrc AUTHOR
This manual page was written by Bryan Donlan bdonlan@gmail.com for the Debian(TM) system (but may be used by others). Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 2 any later version published by the Free Software Foundation, or the Common Development and Distribution License. Revised by Seth Heeren zfs-fuse@sehe.nl On Debian systems, the complete text of the GNU General Public License can be found in /usr/share/common-licenses/GPL. The text of the Common Development and Distribution Licence may be found at /usr/share/doc/zfs-fuse/copyright COPYRIGHT
Copyright (C) 2010 Bryan Donlan [FIXME: source] 2010-06-09 ZFS-FUSE(8)
