HP ProLiant DL380G5-WSS 3.7.0 HP StorageWorks HP Scalable NAS File Serving Sof - Page 152

Disable atime updates for a filesystem, Suspend a filesystem for backups

Page 152 highlights

By default, the atime for a file is updated whenever the file is accessed; however, you may want an update to occur only after a specific number of seconds have passed since the file was last updated. This can minimize the performance impact of atime updates for files that are accessed frequently (at the cost of sometimes seeing stale access times). To specify an update period, add the following parameter to the mxinit.conf file: psfs_atime_resolution_seconds = The default is 0, which means that atimes are updated whenever files are accessed. If is set to a different value N, then a file's atime will be updated when it is accessed only if it has been at least N seconds since it was last updated. Disable atime updates for a filesystem By default, atime updating is done on all filesystems (other than read-only filesystems) that are mounted on a node on which atime updates have been enabled. However, if you do not want atime updates to occur for a specific filesystem, you can disable the feature for that filesystem. To disable atime updates, mount the filesystem with the -o noatime option. Suspend a filesystem for backups The psfssuspend utility suspends a PSFS filesystem in a stable, coherent, and unchanging state. While the filesystem is in this state, you can copy it for backup and/or archival purposes. When copying directly from a suspended device, be sure to use the raw device (/dev/rpsd/...) to ensure that all of the copied blocks are up-to-date. The filesystem is essentially unusable while it is suspended; however, applications that can tolerate extended waits for I/O do not need to be terminated. IMPORTANT: Do not use psfssuspend to suspend the administrative filesystem (/_adminfs). Doing this can cause issues with the cluster. The psfsresume utility restores a suspended filesystem. The psfssuspend and psfsresume utilities affect the specified filesystem on all servers where it is mounted; however, the utilities should be executed on only one server in the cluster. 152 Configure PSFS filesystems

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By default, the atime for a file is updated whenever the file is accessed; however,
you may want an update to occur only after a specific number of seconds have
passed since the file was last updated. This can minimize the performance impact
of atime updates for files that are accessed frequently (at the cost of sometimes seeing
stale access times).
To specify an update period, add the following parameter to the
mxinit.conf
file:
psfs_atime_resolution_seconds = <seconds>
The default is 0, which means that atimes are updated whenever files are accessed.
If
<seconds>
is set to a different value N, then a file
s atime will be updated when
it is accessed only if it has been at least N seconds since it was last updated.
Disable atime updates for a filesystem
By default, atime updating is done on all filesystems (other than read-only filesystems)
that are mounted on a node on which atime updates have been enabled. However,
if you do not want atime updates to occur for a specific filesystem, you can disable
the feature for that filesystem. To disable atime updates, mount the filesystem with
the
-o noatime
option.
Suspend a filesystem for backups
The
psfssuspend
utility suspends a PSFS filesystem in a stable, coherent, and
unchanging state. While the filesystem is in this state, you can copy it for backup
and/or archival purposes. When copying directly from a suspended device, be sure
to use the raw device (
/dev/rpsd/...
) to ensure that all of the copied blocks are
up-to-date.
The filesystem is essentially unusable while it is suspended; however, applications
that can tolerate extended waits for I/O do not need to be terminated.
IMPORTANT:
Do not use
psfssuspend
to suspend the administrative filesystem (
/_adminfs
).
Doing this can cause issues with the cluster.
The
psfsresume
utility restores a suspended filesystem. The
psfssuspend
and
psfsresume
utilities affect the specified filesystem on all servers where it is mounted;
however, the utilities should be executed on only one server in the cluster.
Configure PSFS filesystems
152