Prune Policy: The Prune policy is bundled with the automated Snapshot Scheduler utility as the “upper” threshold on how many snapshot images to be taken and maintained by a Snapshot schedule.
Snapshot Schedules
(click here to see how to examine how much of your storage capacity has been used)
A default 70% upper threshold comes with each Snapshot Container.
Purge Policy: The Purge action is triggered by a capacity threshold value on a specific Snapshot Container. Once the threshold is exceeded, SANWatch will start erasing previous images in order to release storage space. The purge action will continue until there remains a reserve of the minimum number of snapshot images. The reserve can be configured as the minimum number of snapshot images or by the life span of individual snapshot images.
For example, if snapshots’ life span is set to “one week” and a snapshot is taken every day, a Purge action desperately freeing capacity will eventually stop by the reserve consisting of seven images.
Prune Policy: The Prune policy is bundled with the automated Snapshot Scheduler utility as the “upper” threshold on how many snapshot images to be taken and maintained by a Snapshot schedule.
Shown below is an example with a “one week” life span threshold. If one snapshot is taken each day, the first image will be erased on the eighth day.
The scheduler prune policy helps contain the number of snapshot images taken by each snapshot schedule.
Purge Policy on Snapshot Containers & Snapshot Sets
The Purge Rule policy can be configured on an existing Snapshot Container or a Snapshot Set. For example, if there are two Snapshot Sets under a Snapshot Container, you can set a 50% purge policy on one of them in order to control the maximum space used by each Snapshot Set.
Step 1. Under the View and Edit Snapshot Container screen, click to select a Snapshot Container.
Step 2. Right-click to display the related commands, and left-click on Space Utilization Threshold.
Step 3. Your will be prompted by a Space Threshold window. Use the dropdown lists to specify a capacity threshold for a specific container.
Threshold Level Value: Enter a percentage number in the text field. When a percentage threshold is violated, the automated purge control will be initiated.
Policy Code: Select an option from the pull-down list.
The purge control options include:
Notify Event only: A notification level event message will be delivered to notify system administrator.
Warning Event only: A warning level event message will be delivered to notify system administrator.
Critical Event only: A critical level event message will be delivered to notify system administrator.
Critical Event only and Execute Priority-based purge Operation:
Critical Event only and Fail block allocation attempt, making association Image as Invalid:
Critical Event only and Fail IO:
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