Dell PowerVault 725N (Rackmount NAS Appliance) - Manual (Page 44)

Configuring the Persistent Image Global Settings
You can modify the various aspects of the persistent image environment by performing the following steps:
1. Log in to the NAS Manager.
2. Click Disks.
3. Click ActiveArchive.
4. Click Global Settings.
5. Configure the following options.
l Maximum persistent images — Specifies the maximum number of active persistent images per system, up to a maximum of 250. When the
system has 250 persistent images stored, starting another persistent image overwrites the oldest persistent image with the lowest retention
weight.
l Inactive period — Prior to starting a persistent image, the system waits for a period of relative inactivity on the volume being imaged. The default
value for this period, which is 5 seconds, allows systems to start an image with a consistent file set and a minimal time-out. Experienced
administrators may reduce or increase this value for system optimization. Reducing the inactive period allows persistent images to begin on
systems where disk inactivity is rare, at the possible expense of synchronization problems within applications that are concurrently writing to
multiple files.
l Inactive time-out — Specifies the amount of time the system continues to retry to create a persistent image (default time is 15 minutes). A
persistent image cannot start until a period of relative inactivity, specified by Inactive period, occurs. If an interval longer than Inactive time-out
passes before the persistent image can begin, the persistent image cannot be taken and an error is displayed in the NAS Manager status
indicator and logged in the event log.
l Image directory — Specifies the directory name that is to be used for the persistent image mount point. Each persistent image appears as a
subdirectory in the volume that is being imaged. The entire content of the volume, as it existed when the persistent image was created, appears
under this directory.
6. If you need to re-establish the system defaults, click Restore Defaults.
7. Click OK to update the global settings.
Configuring Persistent Image Volume Settings
You can modify volume settings by performing the following steps:
1. Log in to the NAS Manager.
2. Click Disks.
3. Click ActiveArchive.
4. Click Volume Settings.
5. Select the volume that you want to reconfigure.
6. Click Configure.
7. Use the appropriate menus to configure the following options.
l Warning threshold reached when — Defines the percentage of cache space used that triggers warning messages to the system event log.
l Begin deleting images when — Defines the percentage of cache space used that triggers automatic deletion of the oldest persistent images with
the lowest retention weight on the system. Automatic persistent image deletions are recorded in the system log.
l Cache size — Specifies the percentage of the volume that is allocated to the cache file. Increasing this value allows more and larger persistent
images to be maintained. Ensure that adequate space is available on the persistent image files' location drive.
8. If you need to re-establish the system defaults, click Restore Defaults.
9. Click OK.
Using Persistent Images
In addition to scheduling persistent images, you can take new persistent images on demand, delete existing persistent images, configure the persistent image
environment, and set persistent image retention weights.
Taking a New Persistent Image on Demand
1. Log in to the NAS Manager.
2. Click Disks.
3. Click ActiveArchive.
NOTE: Before changing the image directory name, you must delete all existing persistent images.
NOTE: Before changing the cache size, you must delete all persistent images on that volume.