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Delphix

Data Compression May Be Inhibited (TB014)

Impact

The Delphix Engine implements several mechanisms for optimizing storage utilization. One such mechanism is on-disk data compression. As a result of this issue, some newly created dSources or Virtual Databases (VDBs) may not be compressed and will utilize more storage than expected. Depending on the size of the affected dSources and VDBs, available storage capacity may be depleted, impacting the performance and functionality of other operations on the Delphix Engine.

Contributing Factors

This issue only affects systems that are upgraded from Delphix Engine 2.6.x to Delphix Engine 2.7.0, Delphix Engine2.7.1, or Delphix Engine 2.7.2

Systems that were initially installed with Delphix Engine 2.7.x or later are not impacted, even if upgraded later.

All dSources and VDBs are contained in a Database Group. dSources and VDBs are more likely to be impacted when the Database Group with which they are associated was created after an affected software upgrade.

SnapShots of dSources or VDBs created before the upgrade are not impacted.

Symptoms

Unexpected disk utilization, especially during creation of a new dSource or use of a newly-created VDB. If available storage becomes severely constrained, storage alerts may occur.

Relief/Workaround

Delphix Support can apply a workaround that will permanently prevent recurrence of the problem. And Support can identify any affected VDBs or dSources. Application of the workaround does not require a service disruption or software changes, and it can be quickly completed.

Once the workaround has been implemented, affected dSources and VDB will remain uncompressed. Freeing up the additional space used by these objects will require deleting,  then re-creating, the objects. Objects created after the workaround is applied will result in normal compression.

If sufficient storage capacity exists such that affected dSources and VDBs do not adversely constrain available capacity, no immediate action is required. However, the workaround should still be implemented to prevent additional unexpected storage usage.

Resolution

A final resolution is available in Delphix Engine 2.7.3 and later releases.