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.
/usr/sbin/freezefs [-t time] mount_point
/usr/sbin/freezefs [-q] mount_point
/usr/sbin/thawfs mount_point
Query if the AdvFS domain specified by mount_point is
frozen. 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.
Mount point of the filesystem.
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 metadataconsistent
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.
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.
You must be root user to run freezefs and thawfs.
Success. An error occurred.
These examples show the use of the evmget, evmwatch, and
evmshow commands 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 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 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
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.
Commands: evmget(8), evmshow(8), evmwatch(8), thawfs(8)
freezefs(8)
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