Tag Archives: PVSCSI

Understanding VMware ESXi Queuing and the FlashArray

So I am in the middle of updating my best practices guide for vSphere on FlashArray and one of the topics I am looking into providing better guidance around is ESXi queue management. This breaks down to a few things:

  • Array volume queue depth limit
  • Datastore queue depth limit
  • Virtual Machine vSCSI Adapter queue depth limit
  • Virtual Disk queue depth limit

I have had more than a few questions lately about handling this–either just general queries or performance escalations. And generally from what I have found it comes down to fundamental understanding of how ESXi queuing works. And how the FlashArray plays with it. So I put a blog post together of a use case and walking through solving a performance problem. Explaining concepts along the way.

Please note:

  • This is a simple example to explain how queuing works in ESXi
  • Mileage will vary depending on your workload and configuration
  • This workload is targeted specifically to make relationships easier to understand
  • PLEASE do not make changes in your environment at least until you read my conclusion at the end. And frankly not without direct guidance from VMware support.

I am sorry, this is a long one. But hopefully informative!
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