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

−qQuery 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.

> 0An 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)