Unity 380XT granularity question

Question

Hello. Our 380XT has been periodically taking its active SP offline, causing multiple VMs to crash when it does. I had a multi-month case open with Dell engineers and their recommendation came down to lowering the unmap rate and lowering the unmap granularity in vSphere on our datastores. They referred me to vmware for making that change.

Crucially, vmware says this (emphasis added by me):

Granularity defines the minimum size of a released space sector that underlying storage can reclaim. Storage cannot reclaim those sectors that are smaller in size than the specified granularity. For VMFS6, reclamation granularity equals the block size. When you specify the block size as 1 MB, the granularity is also 1 MB. Storage sectors of the size smaller than 1 MB are not reclaimed.

Note:Certain storage arrays recommend an optimal unmap granularity. ESXi supports automatic unmap processing on arrays with the recommended unmap granularity of 1 MB or greater, for example 16 MB,. On the arrays with the optimal granularity of 1 MB and less, the unmap operation is supported if the granularity is a factor of 1 MB. For example, 1 MB is divisible by 512 bytes, 4 KB, 64 KB, and so on.

Would anyone happen to know if the 380XT has a recommended unmap granularity? I posed the question to Dell and they never followed up. Thank you.

DELL-Josh Cr · Answer

Hi, Thanks for your question.  I don’t see any official recommendations for how it should be configured.

Unity

Unity 380XT granularity question

Was this post helpful?