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 VMware and VAAI

Cameron Sams's profile image
Cameron Sams posted 02-28-2022 17:22
I am running vcenter 7.  I have a G350 array with a tiered thin-provisioned pool.  The host indicates VAAI is supported and I am testing some of the features.  One of these is the block zeroing.  I have provisioned a couple of thick eager VMDKs to a VM but I do not see this storage consumed on the LDEV.  Its only when I start writing to the drive that I see the space being consumed.  Is there some smarts in the array that no longer allows block zeroing?
William Jansen van Nieuwenhuizen's profile image
William Jansen van Nieuwenhuizen

I'm not sure what you're expecting. But the volume filling up as things gets written to it sounds like the right behavior.

As for block zeroing and VAAI support, those features are enabled on the array via the 'host mode options' you specify on your host groups. Below is a link to some of the popular host modes on Hitachi arrays, including zeroing support(114) and VAAI(54&63): 

So check your host group if you're not getting the intended behavior, it's more likely a host mode setting that's missing.