freezefs(8)freezefs(8)NAME
freezefs, thawfs - The freezefs utility causes the specified fileset's
domain to enter into a metadata stable state. All the filesets in the
AdvFS domain are affected. The thawfs utility causes a previously
frozen fileset's domain to resume normal activity.
SYNOPSIS
/usr/sbin/freezefs [-t time] mount_point
/usr/sbin/freezefs [-q] mount_point
/usr/sbin/thawfs mount_point
OPTIONS
Query if the AdvFS domain specified by mount_point is frozen. Speci‐
fies the maximum time allowed for the fileset's domain to remain
frozen:
> 0 Specifies the timeout value in seconds.
= 0 Uses the default timeout specified in the vfs stanza of
/etc/sysconfigtab as freezefs_default_timeout. If not specified
in/etc/sysconfigtab, freezefs uses 60 seconds.
< 0 Specifies no timeout. The fileset's domain remains frozen
until explicitly thawed by way of /usr/sbin/thawfs.
Certain system events on a cluster will cause automatic thaws
regardless of timeout value. See DESCRIPTION for more informa‐
tion.
OPERANDS
Mount point of the filesystem.
DESCRIPTION
To allow coherent hardware snapshots in multivolume domain configura‐
tions, filesystem metadata must be consistent across all volumes when
the individual volumes are snapped or cloned. These configurations
include both multivolume AdvFS domains and multivolume LSM logical vol‐
umes.
The freezefs command places the filesystem in a metadata-consistent
state and guarantees that it stays that way until thawed. All metadata,
which could be spread across multiple volumes or logical units (LUNs),
is flushed to disk and does not change for the duration of the freeze.
The filesystem thaws either by timing out or explicitly with the thawfs
command. If you are running a cluster configuration, shutting down any
node or the failure of any node will also thaw the filesystem.
The exact nature of the freezefs command depends on whether you are
running on a single system or a cluster.
Single System
When you freeze a filesystem, any in-process metadata updates are
allowed to finish. Filesystem operations that do not modify metadata
are allowed while frozen. Some operations will work normally even if
the target fileset's domain is frozen, for example: Read Non-extending
write Stat
Filesystem operations that modify metadata are blocked. The following
operations will block if the target fileset's domain is frozen, for
example: Mount of fileset rmvol Extending write mkfset or rmfset
The following filesystem operations will fail immediately if the target
filesystem (that is, domain) is frozen: Mount update of fileset Unmount
of fileset
Cluster
When you freeze a filesystem in a clustered configuration, all in-
process filesystem operations are allowed to complete. Some filesystem
operations are allowed while frozen. The following operations, which do
not require metadata updates, will work normally even if the target
filesystem is frozen. Read Stat
Most new filesystem operations are blocked when the filesystem is
frozen. Operations that have the potential for requiring metadata
updates will block if the target filesystem is frozen, for example:
Write chmod Link rmvol
Some filesystem operations will fail immediately if the target domain
is frozen, for example: Unmount of fileset Mount (update) of fileset
User-initiated planned relocation User-initiated forced unmount
The freezefs command posts an event manager (EVM) event when a file
system is frozen or thawed. Use the evmwatch and evmshow commands to
determine if any file systems in the cluster are frozen. See EXAMPLES.
NOTES
At present, freezefs and thawfs functionality is only implemented for
AdvFS filesystems.
Entering the freezefs or thawfs command for a single mount point
affects all filesets in the domain.
In a cluster configuration, some system events may cause an automatic
thawfs regardless of the timeout -t option. See the DESCRIPTION section
for more information.
RESTRICTIONS
You must be root user to run freezefs and thawfs.
EXIT STATUS
Success. An error occurred.
EXAMPLES
These examples show the use of the evmget, evmwatch, and evmshow com‐
mands to determine if any file systems in the cluster are frozen. This
example shows the message received on a successful freeze of a file
system.
# /usr/sbin/freezefs /freezetest
freezefs /freezetest: Successful This example shows how to ver‐
ify that the file system has been frozen.
# evmget -f”[name sys.unix.fs.vfs.freeze]” | evmshow -t “@time‐
stamp@@”
19-Dec-2001 14:16:51 VFS: filesystem test2_domain#freeze mounted
on /freezetest was frozen This example gives verification that a
thaw was successful.
# /usr/sbin/thawfs /freezetest
thawfs /freezetest: Successful This example gives a time stamp
for a successful thaw.
# evmget -f”[name sys.unix.fs.vfs.thaw]” |evmshow -t “@timestamp
@@”
19-Dec-2001 14:17:32 VFS: filesystem test2_domain#freeze mounted
on /freezetest was thawed This example shows a query using the
freezefs command when the mount point is already frozen.
# freezefs-q /unixaccts
/unixaccts is frozen This example shows a query using the
freezefs command when the mount point is not frozen.
# freezefs-q /unixaccts
/unixaccts is not frozen
ERRORS
The following describes error messages and explanations: freezefs: No
such file or directory thawfs: No such file or directory
File named by pathname, mount_point does not exist.
Cluster: mount_point was forced unmounted or became NOT_SERVED.
freezefs: Invalid argument thawfs: Invalid argument
File named by mount_point exists but is not a mount point.
freezefs: error, cannot freeze /, /usr or /var thawfs: error,
cannot freeze /, /usr or /var
Freezing of root (/), /usr, or /var not supported. freezefs:
error, permission denied - root privilege required thawfs:
error, permission denied - root privilege required
Must have root privilege to run freezfs and thawfs. freezefs:
Operation already in progress
Fileset mounted on mount_point already frozen. thawfs: Opera‐
tion already in progress
Fileset mounted on mount_point already thawed or thaw in
progress. freezefs: Function not implemented thawfs: Function
not implemented
Fileset mounted on mount_point is an invalid filesystem type
(must be AdvFS).
Cluster: mount_point is a filesystem that is HSM managed.
freezefs: I/O error thawfs: I/O error
Fileset mounted on mount_point specifies a domain in panicked
state. freezefs: Host is down thawfs: Host is down
Cluster only: A node has failed or is being shut down. Try
again. freezefs: Operation would block
Cluster only: Domain busy. Try again.
SEE ALSO
Commands: evmget(8), evmshow(8), evmwatch(8), thawfs(8)freezefs(8)
