Mixing SAS HDD's and SSD's in a traditional RAID 10 array?

Offtopic Chat
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A question came up today about how to handle a situation with a piece of legacy equipment that has no upgrade path. It has what is basically a Supermicro server embedded in it and uses an LSI MegaRAID 9271 SAS controller to handle its drives. The current drives are ancient Seagate Cheetah SAS 15.7k 300GB units. One drive in a RAID10 array has died, and they are out of spare drives on-site. As opposed to taking the chance with used drives from ebay, can they use a SAS SSD drive instead? They do have some Hitachi enterprise 800GB SAS SSD drives on site that can be made to fit in the drive basy using a 2.5 to 3.5 adapter for the Supermicro drive trays.
Assuming the controller can even see the drives, what would be the issues from doing this due to the different performance levels of the HD vs SSD drive? My thought was that if this works, they could go through and replace the other three drives in the array one at a time with SSD’s so all the drives have the same performance.

And yes, they do have tested backups of this to restore from.

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It’ll work fine. They won’t see much of a performance boost unless and until they replace the last of the rust drives, though.

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I will pass this along. The SSD’s are new/unused but still fairly old as well. Is it possible to still buy current manufactured new SAS SSD’s in under 1TB sizes?

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I’m not sure anybody is still manufacturing SAS SSDs, period–but you can typically mix in SATA drives on a SAS controller just fine.

Granted, 12Gbps SAS is a higher performance protocol than 6Gbps SATA, but the differences in underlying drives generally overwhelm the differences between SATA and SAS, in my experience–and any enterprise grade SSD will of course wildly outperform those elderly Cheetahs. :cowboy_hat_face:

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Something like a Kingston 480GB DC600M would be a good replacement then if they want something new?

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Yep. Or larger capacity, if you want longer endurance.

Remember, endurance is a certain number of Full Drive Writes–so with the same write workload, a 2T Kingston dc600m will have roughly six times the endurance (and therefore, useful lifespan before slowdown and eventual failure) of the 480G part.

You may still want the cheaper part that won’t perform at its best for as long, and if so, that’s okay–that can be valid, and I’m not trying to make your decisions for you, I just want to make sure you know what decision you’re making and what its alternatives are. :slight_smile: