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mfsmount

Mount MooseFS.

This page reproduces the manual page mfsmount(8) as the product ships it: the text man mfsmount prints on a machine where the packages are installed. It is not edited here, and where it disagrees with the rest of this documentation, the documentation is the side kept against the sources. What the subject is: Command line tools.

Synopsis​

mfsmount [HOST[:PORT]:[PATH]] [options] mountpoint

mfsmount -h|--help

mfsmount -V|--version

Since 3.0.75 (Linux only):

mount -t moosefs [options] [HOST[:PORT]:[PATH]] mountpoint

Description​

Mount MooseFS.

Options​

GENERAL OPTIONS​

  • -h, --help
    display help and exit

  • -V
    display version information and exit

FUSE OPTIONS​

  • -d, -o debug
    enable debug mode (implies -f)

  • -f
    foreground operation

  • -s
    disable multi-threaded operation

MOOSEFS OPTIONS​

  • -c CFGFILE, -o mfscfgfile=CFGFILE
    loads file with additional mount options

  • -m, --meta, -o mfsmeta
    mount MFSMETA companion filesystem instead of primary MooseFS

  • -n
    omit default mount options (-o allow_other)

  • -p
    prompt for password (interactive version of -o mfspassword=PASS)

  • -H HOST, -o mfsmaster=HOST
    connect with MooseFS master on HOST (default is mfsmaster)

  • -P PORT, -o mfsport=PORT
    connect with MooseFS master on PORT (default is 9421)

  • -B IP, -o mfsbind=IP
    local address to use for connecting with master and chunkservers instead of the default one

  • -L IP, -o mfsproxy=IP
    define listen ip address of local master proxy for communication with tools (default: 127.0.0.1)

  • -S PATH, -o mfssubfolder=PATH
    mount specified MooseFS directory (default is /, i.e. whole filesystem)

  • -o mfspassword=PASSWORD
    authenticate to MooseFS master with PASSWORD

  • -o mfspassfile=FILENAME
    authenticate to MooseFS master with password stored in first line of file pointed by FILENAME

  • -o mfsmd5pass=MD5
    authenticate to MooseFS master using directly given MD5 (only if mfspassword option is not specified)

  • -o nonempty
    allow to mount MFS in a non-empty directory. Notice! This option is available to use only if the locally installed FUSE library allows it.

  • -o mfsdebug
    print some MooseFS-specific debugging information

  • -o mfsmemlock
    try to lock memory (all allocated memory will be mapped to physical RAM - which also means no swapping)

  • -o mfsallowoomkiller
    do not disable out of memory killer (Linux only)

  • -o mfslogminlevel=LEVEL
    minimal message level to log ([D]EBUG,[I]NFO,[N]OTICE,[W]ARNING or [E]RROR - default is INFO)

  • -o mfslogelevateto=LEVEL
    send messages with log level lower than LEVEL to syslog as LEVEL (levels as above - default in NOTICE)

  • -o mfslimitarenas=N
    if N>0 then limit glibc malloc arenas (Linux only - default: 4)

  • -o mfsflattrash
    use flat trash structure in meta (option added for compatibility reasons - since version 3.0.64 trash is split into 4096 subfolders which reduces problems with big trashes)

  • -o mfsdelayedinit
    connection with master is done in background - with this option mount can be run without network (good for being run from fstab / init scripts etc.)

  • -o mfsmkdircopysgid=N
    sgid bit should be copied during mkdir operation (default depends on operating system)

  • -o mfssugidclearmode=SMODE
    set sugid clear mode (see SUGID CLEAR MODES; default depends on operating system)

  • -o mfscachemode=CMODE
    set cache mode (see DATA CACHE MODES; default is FBSDAUTO on FreeBSD, AUTO on all other OSes)

  • -o mfscachefiles
    (deprecated) preserve file data in cache (equivalent to '-o mfscachemode=YES')

  • -o mfsreaddirplusminto=SEC
    set minimal entry/attributes cache timeout for readdirplus in seconds (default: 0.0001, max: 60.0)

  • -o mfsattrcacheto=SEC
    set attributes cache timeout in seconds (default: 1.0, max: 86400.0)

  • -o mfsxattrcacheto=SEC
    set extended attributes (xattr) cache timeout in seconds (default: 30.0, max: 86400.0)

  • -o mfsentrycacheto=SEC
    set file entry cache timeout in seconds (default: 0.0, i.e. no cache, max: 86400.0)

  • -o mfsdirentrycacheto=SEC
    set directory entry cache timeout in seconds (default: 1.0, max: 86400.0)

  • -o mfsnegentrycacheto=SEC
    set negative entry cache timeout in seconds (default: 0.0, max: 86400.0)

  • -o mfssymlinkcacheto=SEC
    set symbolic link cache timeout in seconds (default: 300.0, max: 86400.0)

  • -o mfsgroupscacheto=SEC
    set supplementary groups cache timeout in seconds (default: 300.0, max: 86400.0); setting this value to 0 disables supplementary groups support

  • -o mfsrlimitnofile=N
    try to change limit of simultaneously opened file descriptors on startup (default: 100000)

  • -o mfsnice=LEVEL
    try to change nice level to specified value on startup (default: -19)

  • -o mfswritecachesize=N
    specify write cache size in MiB (in range: 16..2048 - default: 256)

  • -o mfsreadaheadsize=N
    define size of all read ahead buffers in MiB (in range: 16..2048 - default: 256)

  • -o mfsreadaheadleng=N
    define amount of bytes to be additionally read (in range: 128KiB..2MiB - default: 1048576)

  • -o mfsreadaheadtrigger=N
    define amount of bytes read sequentially that turns on read ahead (default: 10 * mfsreadaheadleng)

  • -o mfserroronlostchunk
    when all known chunkservers are connected to the master and the required chunk is missing then immediately finish I/O and return an error

  • -o mfserroronnospace
    when all known chunkservers are connected to the master and there is no free space then immediately finish I/O and return an error

  • -o mfsioretries=N
    specify number of retries before I/O error is returned (default: 30)

  • -o mfstimeout=N
    define maximum timeout in seconds before I/O error is returned (default: 0 - which means no timeout)

  • -o mfslogretry=N
    define minimal retry counter on which system will start log I/O messages (default: 5)

  • -o mfsfsyncmintime=SEC
    force fsync before last file close when file was opened/created at least SEC seconds earlier (default: 0.0 - always do fsync before close)

  • -o mfspreflabels=LABELEXPR
    specify preferred labels for choosing chunkservers during I/O

  • -o mfsnoxattrs
    turn off xattr support

  • -o mfsnoposixlocks
    turn off support for global posix locks (lockf + ioctl) - locks will work locally

  • -o mfsnobsdlocks
    turn off support for global BSD locks (flock) - locks will work locally

MOUNT OPTIONS​

General mount options (see mount(8) manual):

  • -o rw|-o ro
    Mount file-system in read-write (default) or read-only mode respectively.

  • -o suid|-o nosuid
    Enable or disable suid/sgid attributes to work.

  • -o dev|-o nodev
    Enable or disable character or block special device files interpretation.

  • -o exec|-o noexec
    Allow or disallow execution of binaries.

Files​

  • mfsmount.cfg
    configuration file for MooseFS mount daemon; refer to mfsmount.cfg(5) manual for details

Notes​

SUGID CLEAR MODE​

During attribute change file systems sometimes clear flags suid and/or sgid. Behavior is different on different file systems. MFS tries to mimic behavior of most popular file system on given operating systems.

  • NEVER
    MFS will not change suid and sgid bit on chown

  • ALWAYS
    clear suid and sgid on every chown - safest operation

  • OSX
    standard behavior in OS X and Solaris (chown made by unprivileged user clear suid and sgid)

  • BSD
    standard behavior in *BSD systems (like in OSX, but only when something is really changed)

  • EXT
    standard behavior in most file systems on Linux (directories not changed, others: suid cleared always, sgid only when group exec bit is set)

  • XFS
    standard behavior in XFS on Linux (like EXT but directories are changed by unprivileged users)

DATA CACHE MODES​

There are four cache modes: DIRECT, NO, YES and AUTO. Default option is AUTO and you shouldn't change it unless you really know what you are doing. In AUTO mode data cache is managed automatically by mfsmaster. On FreeBSD there is an additional mode called FBSDAUTO.

  • DIRECT
    forces direct io (bypasses cache)

  • NO,NONE or NEVER
    always flush data cache on open (safest but can reduce efficiency)

  • YES or ALWAYS
    always keep data cache on open (dangerous)

  • AUTO
    file cache is managed by mfsmaster automatically (should be very safe and efficient)

  • FBSDAUTO
    (mode available on FreeBSD system only) AUTO, but if the system detects a kernel that might have problems with AUTO mode it falls back to DIRECT mode

LABEL EXPRESSIONS​

LABELEXPR grammar:

  • LABELEXPR
    -> S ; LABELEXPR | S

  • S
    -> S + M | M

  • M
    -> M L | L

  • L
    -> a .. z | A .. Z | ( S ) | [ S ]

Subexpressions should be placed in priority order. Up to nine subexpressions (priorities) can be specified.

FSTAB​

On most Unix systems mfsmount can be invoked automatically from /etc/fstab. Be aware that rw or ro option has to be specified in options. Also on many systems there should be option which informs the system that this mountpoint should be mounted after starting networking services (options such as _netdev or late).

Linux:

mfsmount mountpoint fuse options 0 0

*BSD:

mfsmount_magic mountpoint moosefs options,mountprog=/usr/local/bin/mfsmount 0 0

Since version 3.0.75 alternative form can be used:

Linux:

HOST[:PORT]:[PATH] mountpoint moosefs options 0 0

*BSD:

HOST[:PORT]:[PATH] mountpoint moosefs options,mountprog=/usr/local/bin/mfsmount 0 0

TRASH​

The companion "meta" filesystem that can be mounted using options -m, --meta, -o mfsmeta, exposes two types of files that are no longer visible in the main filesystem: deleted files with trashretention >0 and sustained (deleted but opened or recently closed) files. The meta filesystem has two directories: sustained and trash. Inside the trash directory there are 4096 subdirectories, called from 000 to FFF and a directory called undel. Inside the 000 to FFF directories there are deleted files, that show their original paths in the filesystem with | sign. There is a limited number of operations that can be performed on these files: remove permanently or restore. To restore a file to the original filesystem, you can move it to the undel directory. MooseFS will try to restore it to the original path, if that doesn't exist anymore then it will be created (with root credentials). The 000 to FFF directories are to prevent showing all deleted files in one directory, in case your system has a LOT of them (milions of files in one directory can lead to unexpected kernel behaviours, especially on older kernels). If you know your system doesn't have a lot of deleted files, you can mount a "flat" trash by using the -o mfsflattrash option, then all deleted files will be visible directly in the trash directory. The sustained directory contains all sustained files, without any extra subdirectories. They are there just to browse them.

SPECIAL FILES​

Each mount exposes several special, hidden files, that are accessible only in the root of this mount and provide the user with special information about their MooseFS instance. These files are:

  • .masterinfo
    displays information about master server (leader in Pro version) in binary format; this file is used by various MooseFS commandline tools

  • .stats
    displays statistics about performed i/o commands

  • .oplog
    displays the log of current operations performed by the mount; this file never sends EOF (use ctrl+c to stop cat)

  • .ophistory
    displays some operation log history (up to circa 16 MiB of data) and then current operations performed by the mount (use ctrl+c to stop cat)

  • .params
    displays mount's working parameters; this file is readable only by root

  • .random
    very fast pseudo-random bytes generator

  • .mooseart
    displays a moose in ascii art :)

See also​

mfsmaster(8), mfstools(1), mfsmount.cfg(5), mount(8)