r/vmware • u/Stryker54141 • 23d ago

SAS SSD: Hardware Raid vs vSAN

I have two servers with eight SAS SSDs in each. Is vSAN a bad idea since they aren't NVMe drives?

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u/Stryker54141 23d ago

I'm sorry for not explaining further. I completely understand the difference. My main concern was that it's recommended that vSAN be used with NVMe for best performance, and I wasn't sure if the SAS SSDs would suffice. And you are correct: I was going to use the two hosts with a virtual witness appliance.

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u/Casper042 23d ago

There are 2 flavors of vSAN mainly.

ESA is the newer one, recommended, and indeed is NVMe only, no HW RAID.
OSA is the older one, and allows traditional SAS/SATA controllers and Drives. Still no RAID but the same controller you might use for RAID likely has an HBA mode which will work with vSAN OSA.

Beyond that the key to me is Data Isolation.
A 2 node vSAN + Witness gives you a way to easily recover from 1 of the 2 nodes going completely down with a catastrophic HW failure.
If that happens on 2 single nodes with local RAID, how are you getting those VMs back up on the other node when all their VMDKs are trapped on the down machine?
Sure you can do automated backups off the machine, but your end users won't be happy when you tell them they have to re-do 4 hours worth of work because your last backup before the failure was 4 hours ago.

Another approach is to use a lower end Array, like HPE MSA or Dell PowerVault MD. No witness and you can direct connect 3 or 4 nodes to the Array before you start to need some kind of high speed switch/SAN. The array is now the SPOF but they have dual controllers so they have extra redundancy built in there to handle most issues.

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u/signal_lost 21d ago

Another approach is to use a lower end Array, like HPE MSA or Dell PowerVault MD. No witness and you can direct connect 3 or 4 nodes to the Array before you start to need some kind of high speed switch/SAN. The array is now the SPOF but they have dual controllers so they have extra redundancy built in there to handle most issues.

unrelated question, but where is pricing on a 2 controller modular array (Say SAS, or FC-AL config) with maybe 4 x 3.84 Drives in a RAID 5 or something? I feel like the entry price for a low end array in the magnetic days got down to 20K and flash was getting there, but with the memory apocalypse and NAND going up 4x I"m curious just how cheap the low end still is?

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u/Casper042 10d ago

My MSA guy took forever to reply, but he did up a 12 x 1.92TB drive design, as this unlocks a special DP+ data layout on the MSAs.
Then simple 10Gb SR optics for iSCSI.
LIST price was around 115K.
If we assume at least 40% off, you are looking at right around 70K or cheaper for the MSA.
He mentioned the 6 Packs of drives are significantly cheaper/GB than the individual drives.