Boot only disks SATA vs SAS
If I am booting a VSphere Host server from local disks but ALL of the VMFS volumes are on the SAN, does it really matter that much what I use for the local disks (SAS vs SATA?). NONE of the guests will run from the local disks, it’s only the base VSphere load that resides there.
Most of my current servers are Dell and have 2 SATA disks in a RAID 1 (SAS6i controller) but I would like to know if there is any local swapping/logging that might be noticeably improved if I used two 15k SAS drives instead ?
Most of my current servers are Dell and have 2 SATA disks in a RAID 1 (SAS6i controller) but I would like to know if there is any local swapping/logging that might be noticeably improved if I used two 15k SAS drives instead ?
David
If you are IO bound, then you could see 2 or 3X better performance.
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Not really, the file system for the virtual machine is on the SAN, so the improvement would be marginal at best.
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You could go in and configure VMware to store swap files on the local disk (not the default, default is with the .vmdk file). However I wouldn't do that. The core VMware OS doesn't need much speed at all, it works great off tiny slow CF cards.
Agreed, missed the part about this being just the host server. Only reason to go with SAS is the drives have better ECC / error recovery timings, and such. Enterprise SATA is not quite as good, and consumer/desktop SATA is unacceptable, as far as I am concerned.
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Thanks, this answers my question and with good explanation. Good point about the CompactFlash, too. I had always assumed that SATA was sufficient but always wondered if I was missing something. Thanks to all for the confirmation.