MOUNT.LUSTRE(8)

NAME
mount.lustre, mount.lustre_tgt - mount helper for Lustre client/target service

SYNOPSIS
mount -t lustre [-o OPTIONS] MGSNAME:/FSNAME CLIENT_MOUNTPOINT
mount -t lustre_tgt [-o OPTIONS] BLOCK_DEVICE SERVER_MOUNTPOINT

DESCRIPTION
mount.lustre and mount.lustre_tgt are used to start a Lustre client or target service, respectively. They should not be called directly; rather they are helper programs invoked through mount(8) as above when the lustre or lustre_tgt filesystem type is used. Lustre clients and targets are stopped by using the umount(8) command. When mounted, Lustre clients will have parameters set according to what is described in /etc/lustre/mount.client.params, and/or the /etc/lustre/mount.FSNAME.params file, with lines of the same style as lctl-set_param(8), with lines of the form PARAM=VALUE.

There are two forms for the device option passed to the mount command, depending on whether a client or a target service is started:

MGSNAME:/FSNAME[/SUBDIR]
    mounts the Lustre client filesystem named FSNAME (optionally starting at subdirectory SUBDIR within the filesystem, if specified) on the client at the directory CLIENT_MOUNTPOINT, by contacting the Management Service at MGSNAME. The format for MGSNAME is defined below. A client filesystem will typically be listed in fstab(5) for automatic mount at boot time, is usable like any local filesystem, and provides a full POSIX-compilant interface.

BLOCK_DEVICE
    specifies the physical disk or ZFS dataset uses to start the target service formatted by the mkfs.lustre(8) command. The BLOCK_DEVICE may be specified using -LLABEL to find the first block device with that label (e.g. testfs-MDT0000), or by UUID using the -UUUID option. Care should be taken if there is a device-level backup of the target filesystem, which would have a duplicate label and UUID if it is not changed with tune2fs(8) or similar. The mounted target service filesystem at MOUNTPOINT is only useful for df(1) operations to show the current space usage, and appears in /proc/mounts to show the device is in use.

OPTIONS

MGSNAME:=MGSNODE[:MGSNODE]
    The MGSNAME may be a colon-separated list of MGSNODE names where the MGS service may run. Multiple MGSNODE values can be specified if the MGS service is configures for HA failover and may be running on any one of the nodes.

MGSNODE:=MGSNID[,MGSNID]
    Each MGSNODE may specify a comma-separated list of NIDs, if there are different LNet interfaces for the same MGSNODE.

mgssec=FLAVOR
    Specifies the encryption flavour for the initial network RPC connection to the MGS node.

    Non-security flavors are: null, plain, and gssnull, which respectively disable, or have no encryption or integrity features for testing purposes.

    Kerberos flavors are: krb5n, krb5a, krb5i, and krb5p.

    Shared-secret key flavors are: skn, ska, ski, and skpi.

    See lgss_sk(8) for more details. The security flavour for client-to-server connections is specified in the filesystem configuration that the client fetches from the MGS.

skpath=FILE|DIRECTORY
    Path to a file or directory with the keyfile(s) to load for this mount command. Keys are inserted into the KEY_SPEC_SESSION_KEYRING keyring with a description containing "lustre:" and a suffix which depends on whether the context of the mount command is for an MGS, MDT/OST, or client. If no skpath is specified for client mounts, the mount command will automatically check for a keyfile named .lgss in the mount point directory and load it if present. This option is only available when built with --enable-gss.

exclude=OSTLIST
    Start a client or MDT with a (colon-separated) list of known inactive OSTs.

  CLIENT OPTIONS
In addition to the standard options listed in mount(8), Lustre understands the following client-specific options:

flock
    Enable full distributed flock(2) support, coherent across all client nodes also using this mount option. This is useful if applications need coherent userspace file locking across multiple client nodes, has no measurable performance impact in modern (2.x) versions of Lustre, is therefore the recommended mode, and is enabled by default in Lustre 2.12.3 and newer.

localflock
    Enable local flock(2) support, using only client-local file locking. This is faster than mounting with the flock option, and can be used for applications that depend on functioning flock(2) but run only on a single node.

noflock
    Disables flock(2) support entirely. Applications calling flock(2) will get an ENOSYS error. It is possible to mount clients with different options, and only those mounted with flock will be coherent amongst each other.

lazystatfs
    Allows statfs(2) (as used by df(1) and lfs-df(1)) to return even if some OST or MDT is unresponsive or has been temporarily or permanently disabled in the configuration. This avoids blocking until all of the targets are available. This is the default since Lustre 2.9.0.

nolazystatfs
    Requires that statfs(2) block until all OSTs and MDTs are available and have returned space usage.

user_xattr
    Enable get/set of extended attributes by regular users. See the attr(5) manual page.

nouser_xattr
    Disable use of extended attributes by regular users. Root and system processes can still use extended attributes.

always_ping
    Force a client to keep pinging even if servers have enabled suppress_pings.

verbose
    Enable mount/remount/umount console messages.

noverbose
    Disable mount/remount/umount console messages.

user_fid2path
    Enable FID to path translation by regular users via lfs fid2path.

nouser_fid2path
    Disable FID to path translation by regular users. Root and process with CAP_DAC_READ_SEARCH can still perform FID to path translation.

network=NET
    Limit connections from the client to be on the network NID specified by 'net'. 'net' designates a single network NID, like 'o2ib2' or 'tcp1'. This option can be useful in case of several Lustre client mount points on the same node, with each mount point using a different network. It is also interesting when running Lustre clients from containers, by restricting each container to a specific network.

    Warning! 'network' option is incompatible with LNet Dynamic Peer Discovery. If you want to restrict client NID, please make sure LNet Dynamic Peer Discovery is disabled.

mgsname=MGSNAME
    Specify a custom hostname for the MGS that will be displayed in /proc/mounts instead of the resolved IP address. The network type (e.g., @tcp, @o2ib) is automatically extracted from the first MGS NID in the device string and should be included in the hostname. If this option is not specified and the device string contains a hostname (not an IP address), the hostname will be automatically extracted and used to generate the mgsname option. This option is purely cosmetic and does not affect the actual connection to the MGS, which is still determined by the device string. This can be useful for making mount entries more readable in system monitoring tools and if MGSNAME is specified as a hostname with DNS resolution that resolves to multiple NIDs instead of numeric addresses.

test_dummy_encryption
    Enable test dummy encryption mode.

noencrypt
    Disable Lustre client-side encryption. By default, Lustre client-side encryption is enabled, letting users define encryption policies on a per-directory basis. fscrypt userspace tool can be used for that purpose, see https://github.com/google/fscrypt

retry=NUM
    Specify the number of times the mount attempt may be retried by the client, with an interval starting at 32 seconds for the first 5 minutes, and doubling for every two retries after that.

  SERVER OPTIONS
In addition to the standard mount options and backing disk type (e.g. ldiskfs) options listed in mount(8), Lustre understands the following server-specific options:

acl Enable POSIX Access Control List support for all clients. See the acl(5) manual page.

no_create
    Do not allow objects to be created on an OST, or new directories on an MDT after mounting. This allows a (potentially newly-formatted) MDT or OST to be started without clients starting to use it immediately. To allow the new target to be used for allocation, unmount and mount the target again without this option, or run 'lctl set_param obdfilter.FSNAME-OSTXXXX.no_create=0' or 'lctl set_param mdt.FSNAME-MDTXXXX.no_create=0' on the appropriate server node. NOTE: this does not start the OST or MDT read-only, it only disables the creation of new objects there. This means existing objects can be be read, modified, or deleted. If the OST or MDT is new then it will not have any objects on it yet.

nosvc
    Only start the MGC (and MGS, if co-located) for a target service, and not the actual MDS or OSS service.

noclient
    Do not allow any client connections other than the local interface to the local MGS. This is helpful for the lctl replace_nids and clear_conf commands to prevent unwanted client connections.

nomgs
    Start an MDT with a co-located MGS without starting the MGS service.

noscrub
    Do not trigger OI scrub automatically when an inconsistency is detected. It is still possible to start explicitly using the lctl lfsck_start.

skip_lfsck
    Do not resume the former paused/crashed LFSCK automatically when mounting.

abort_recov
    Abort client recovery and start the target service immediately.

md_stripe_cache_size=cache_size
    Sets the MD RAID 'stripe_cache_size' parameter to cache_size KiB for server OST or MDT block device with a striped RAID configuration.

recovery_time_soft=timeout
    Allow timeout seconds for clients to reconnect for recovery after a server crash. This timeout will be incrementally extended if it is about to expire and the server is still handling new connections from recoverable clients. The default soft recovery timeout is set to 300 seconds (5 minutes).

recovery_time_hard=timeout
    The server will be allowed to incrementally extend its timeout up to a hard maximum of 'timeout' seconds. The default hard recovery timeout is set to 900 seconds (15 minutes).

BUGS
Not very many mount options can be changed with -o remount.

EXAMPLES
Start a client for the Lustre filesystem testfs at the mount point /mnt/myfilesystem. The Management Service is running on a node reachable via NID cfs21@tcp0:
        # mount -t lustre cfs21@tcp0:/testfs /mnt/myfilesystem

Like above example, but mount subdirectory dir as fileset:
        # mount -t lustre cfs21@tcp0:/testfs/dir /mnt/myfilesystem

Like above example, but the Management Service is running on one of the service nodes mgs1 and mgs2, which are two different hosts separated by a colon and served as a failover pair. Lustre tries the first one, and if that fails, it tries the second one. On each service node, the comma-separated NIDs refer to different interfaces on the same host, and the Lustre client chooses the best one for communication based on which network interfaces are available locally:
        # mount -t lustre mgs1@tcp0,mgs1ib@o2ib0:mgs2@tcp0,mgs2ib@o2ib0:/testfs /mnt/fs

Start the Lustre metadata target service from /dev/sda1 on mountpoint /mnt/test/mdt:
        # mount -t lustre_tgt /dev/sda1 /mnt/test/mdt

Start the testfs-MDT0000 service (by using the disk label), but aborts the Lustre client recovery process for the case that clients are known to be unavailable:
        # mount -t lustre_tgt -L testfs-MDT0000 -o abort_recov /mnt/test/mdt

Mount a client filesystem with a custom MGS name for display purposes. The network type @o2ib will be automatically appended to mgs-cluster in /proc/mounts:
        # mount -t lustre -o mgsname=cfs21@o2ib 10.0.0.2,10.0.0.4@o2ib:/testfs /mnt/myfs

Mount a client filesystem with automatic MGS name generation. The hostname test-mgs will be automatically extracted from the device string and mgsname=test-mgs@tcp will be appended to the list of mount options for display in /proc/mounts:
        # mount -t lustre cfs21@o2ib:/testfs /mnt/myfilesystem

AVAILABILITY
mount.lustre and mount.lustre_tgt are part of the lustre(7) filesystem package. mount.lustre was added in release 0.10.0 mount.lustre_tgt was added in release 2.13.0

SEE ALSO
lfs(1), lustre(7), lctl(8), mkfs.lustre(8), mount(8), tunefs.lustre(8)