Administration - ggRock
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      Automated Snapshot and Writeback Removal

      This article details the settings and usage of the automated snapshot and writeback removal facility within ggRock.

      Problem

      Without maintenance, over time snapshots will collect in your ggRock Array and cause you to run out of space. Writebacks are more transient, meaning they are discarded on every reboot (unless the keep writebacks setting is enabled for a given Machine), however if there is a misconfiguration of your System Image (Make sure to Disable Defragmentation and Windows Update), it is possible for writebacks from all of your systems to quickly build up and fill your array as well because an issue like this is multiplied by the number of systems you have.

      For more information on Writebacks and Snapshots, please refer to "How Writebacks and Snapshots Work".

      Solution

      1. From the ggRock Web UI, click the "Settings" button on the left side.

         

      2. From the "Settings" page, click the "Array and Images" menu item.

         

      3. Under the "Array Settings" subheading, ensure that the "Reserved disk space" value is set to at least 15%, which is the value recommended by the ggRock Team in the "Create, Configure, and Test ggRock Images" manual. The "Warning threshold" setting may be configured to a value of your liking based on how soon you require being notified of an impending full-array situation.

        NOTE:

        It is critical to ensure the reserved disk space setting is used, as the performance of SSDs decreases the closer they are to being completely full due to having to wait for TRIM/erase operations to occur prior to data being written.

         

        • Unutilized Snapshots - Configure a value for how long (in days) for which to retain unutilized snapshots (that is to say, snapshots that have not been activated in this time-period will be eligible for deletion unless they are within the unprotected snapshots).

        • Unprotected Snapshots - Configure a value (in number of snapshots) for snapshots to keep, even if they are eligible for deletion based on their age in the above value.

        • Inactive Writebacks - Configure a value for how long (in hours) to retain writebacks for your systems. Once a writeback is older than this value, it is discarded automatically if the system is not powered on. This helps prevent un-needed writebacks from consuming disk space if the systems are left powered off for an extended period of time.

          Under the "Snapshots and Writebacks Retention Settings", set a value for each of the settings based on your array size and the typical size of your snapshots and writebacks.

      4. Click the "Apply changes" button.