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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
-q Query if the AdvFS domain specified by mount_point is frozen.
-t time
Specifies 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 information.
OPERANDS
mount_point
Mount point of the filesystem.
DESCRIPTION
To allow coherent hardware snapshots in multivolume domain configurations,
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 volumes.
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
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
· addvol
· rmvol
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
0 (Zero)
Success.
> 0 An error occurred.
EXAMPLES
These examples show the use of the evmget, evmwatch, and evmshow commands
to determine if any file systems in the cluster are frozen.
1. This example shows the message received on a successful freeze of a
file system.
# /usr/sbin/freezefs /freezetest
freezefs /freezetest: Successful
2. This example shows how to verify that the file system has been frozen.
# evmget -f"[name sys.unix.fs.vfs.freeze]" | evmshow -t "@timestamp@@"
19-Dec-2001 14:16:51 VFS: filesystem test2_domain#freeze mounted on
/freezetest was frozen
3. This example gives verification that a thaw was successful.
# /usr/sbin/thawfs /freezetest
thawfs /freezetest: Successful
4. 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
5. This example shows a query using the freezefs command when the mount
point is already frozen.
# freezefs -q /unixaccts
/unixaccts is frozen
6. 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: Operation 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)
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Alphabetical
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