SQL Server Memory Shrinking

Question

I had a strange issue today on a 3rd party vendor's SQL Server. This is a VM running SQL Server 2012 SP1. The min and max memory settings are set to 9GB. Task manager showed SQL Server was getting the 9GB. SQL Sentry shows over time the buffer pool was getting smaller until eventually we were not able to connect with SSMS. PLE was in the single digits.

The CPU was at 40% for a couple of days prior and I singled it down to Resource Monitor. This appears to be a symptom of the memory issue.

The vendor restarted the service and everything is back to normal.

I found this KB2845380 and think this might be related but I'm not sure. Has anyone run into something like this before? From what I've been told this has happened every month or so.

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• user507: +1 for the pretty picture, but also I would say patch that instance up to SP2 + CU8 (sqlserverupdates.com). This should include the hotfix noted in that KB article.
• SQLChao: Thanks @ShawnMelton that was my gut instinct but being a box that I don't really administer I wasn't sure if I should look elsewhere before recommending an update.
• user507: Oh, I generally recommend an update before I even continue looking at a server...habit. You might look at the system_health session and diag xel files on the instance, they might show some more information for you.
• Hannah Vernon: Off the top of my head, this sounds to me like memory was removed by the VM manager. If this is VMWare, look into "balloon driver" for tips.
• SQLChao: @MaxVernon I'm aware of VMWare's balloon driver bur have not seen it kick in before. When the host does borrow some memory does the guest OS still show this memory? For instance I have 16 GB on the guest OS. Balloon driver borrows 1GB. If I look at system properties or task manager will I see 16 or 15?

Answer 1

I ended up applying the hotfix for KB2845380 and the issue appears to be resolved.