Nothing but realtime performance stats for datastores... why?

[hellraiser]

Running vCenter 5.0 update 1 with a few ESXi 5.0 u1 hosts and shared storage - performance stats work fine for everything else, if I go to datastores and datastore clusters and look at the performance data it reports "No data available" for all time ranges except realtime (which works as expected). Any idea why?

Cheers

JD

[AndreTheGiant]

All services are working fine? Which DB are you using?

[Paul11]

Look at this KB:

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=200953...

Storage DRS and SIOC Data Counters in vSphere 5.0 Update 1

In vSphere 5.0 Update 1 and later, by default the Storage DRS and SIOC counters are active at the higher statistics collection level 3. This effectively disables non-realtime datastore performance charts. In order to re-enable these performance charts, you can choose to move those counters back to collection level 1. However, moving Storage DRS and SOIC counters to a lower collection level will negatively impact performance, because more statistics are persisted, requiring more I/O and database operations. If you move a large number of data counters from collection level 3 to collection level 1, you might observe the following:

• Loss of statistical data
  A large number of enabled data counters might overwhelm statistics processing, resulting in dropped counters.
  
• Slow roll-ups of statistical data
  The increased number of enabled data counters can cause the statistics roll-up procedures to run slowly. As a result, statistical information might not be available as expected.
  
• Slow purging of statistical data
  The increased number of enabled data counters can slow down purge operations. As a result, statistical information might not be purged as expected.
  

If you want to change the collection levels of Storage DRS and SIOC data counters, you can get support from VMware Global Support Services.

Storage DRS and SIOC Data Counters in vSphere 5.0 Update 1

In vSphere 5.0 Update 1 and later, by default the Storage DRS and SIOC counters are active at the higher statistics collection level 3. This effectively disables non-realtime datastore performance charts. In order to re-enable these performance charts, you can choose to move those counters back to collection level 1. However, moving Storage DRS and SOIC counters to a lower collection level will negatively impact performance, because more statistics are persisted, requiring more I/O and database operations. If you move a large number of data counters from collection level 3 to collection level 1, you might observe the following:

• Loss of statistical data
  A large number of enabled data counters might overwhelm statistics processing, resulting in dropped counters.
  
• Slow roll-ups of statistical data
  The increased number of enabled data counters can cause the statistics roll-up procedures to run slowly. As a result, statistical information might not be available as expected.
  
• Slow purging of statistical data
  The increased number of enabled data counters can slow down purge operations. As a result, statistical information might not be purged as expected.
  

If you want to change the collection levels of Storage DRS and SIOC data counters, you can get support from VMware Global Support Services.

[lingfish]

Hi, I've just come across this issue too, and I'm baffled as to why this behaviour has changed.

Did anyone else see any performance hits, pre U1?  I certainly didn't, and I don't get why anyone would want to lose historical datastore stats (one of the best things to come along in vCenter in a while, IMO).

Just to be clear -- with this new default, I shouldn't expect to see anything other than realtime stats, on datastores, for things like "Aggregate IOPs per Datastore", right?

This seems like a silly backward step to me, especially considering the intelligent rollup and aggregation that vCenter does to those stats.

I realise they can be turned back on, but I'm the type to always wonder why such a bizarre change to a default was made, considering a disinct lack of gripes on the net about performance due to this collection.

[lingfish]

Oh, and the other puzzling thing I can't seem to get clarification on is the difference between AggregateLevel and PerDeviceLevel as reported by Get-PxCounterLevelMapping -- because the DS stats appear to only have 3 now set for the PerDeviceLevel setting.