PowerStore: Metrics reporting for Volume Groups when underlying members change

Changing the members of a Volume Group may cause that Volume Group’s performance and capacity metrics to be reported incorrectly at a specific timescale for a specific time period.

Volumes are removed from a Volume Group. Existing Volumes are added to a Volume Group.

This only affects the Volume Group’s lowest timescale for performance metrics and capacity metrics and only for their associated retention. The lowest timescale for performance metrics is 20 seconds with associated retention of 1 hour. The lowest timescale for capacity metrics is 5 minutes with associated retention of 1 day. This means for Volumes that are removed from a Volume Group, Volume Group performance metrics will no longer include metrics from those removed volumes at the 20-second timescale for 1 hour; Volume Group capacity metrics will no longer include metrics from removed volumes at the 5-minute timescale for 1 day. Other timescales will correctly include these metrics. This also means if a Volume with historical I/O is added to a Volume Group, Volume Group capacity metrics will incorrectly include that Volume’s historical performance metrics at the 20-second timescale for 1 hour and historical capacity metrics at the 5-minute timescale for 1 day. Other timescales will not include metrics for the volume gathered prior to it joining the Volume Group. As noted, this does correct itself over time with all timescales eventually reporting metrics as expected for the Volume Group. Again, this only affects the lowest timescale; other timescales are not affected and can be viewed normally.

Permanent fix:
Recommend upgrading to PowerStore 2.0.0.0 or greater which has a fix for the issue discussed in this article.