Thanks for the quick response.
What would be an example of a random overwrite as opposed to a random write? I agree that WAFL does a great job of coelscing writes and striping them to disk. Are you saying that random overwrites are not handles in the same way as regular writes - meaning they are not handled in NVRAM and destaged to disk (like regular writes)? So, without the benefit of a FlashPool, how would a random overwrite be normally handled?
From what I read yesterday the 3X IOP penalty is there because for every write, the VMkernel has to read metadata from disk, potentially write metadata to disk and finally write the actual block of data to disk. Alignment offset is something different and causes performance issues whether we're dealing with linked clones or any other data that isn't properly aligned. This really isn't an issue so much anymore if you're running a Windows filesystem > XP.
It's more that VMware hasn't officially supported VCAI in a production environment at this point, then any vendor supporting it. I think VCAI is great because it addresses both the management and operational issues of deploying clones into a View environment. VSC is great, but I don't like the fact that View doesn't have complete control over those clones.
Hopefully, NetApp addresses how FlashPools can benefit a View environment more clearly in an upcoming TR. The NetApp VDI sizer is ok, but really doesn't go far enough to properly address how FlashPools should be sized for the VDI worlload.