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performance - Why do servers have SAS instead of SSDs?





I was wondering why do servers still come with SAS disks instead of SSD disks? I know that SAS are faster than normal hard drives but they are still much slower than SSDs. I think they are more expensive too :s



so what's the deal here?


Answer



Cost, capacity and reliability are factors for why SSD adoption hasn't occurred at all levels. SSDs cost more than SAS disks for a given capacity.



But in general, servers don't actually come with a particular type of disk. Storage is something that is configured afterwards.



Some background information: Are SSD drives as reliable as mechanical drives (2013)?




Edit:



Also note that not every workload benefits from SSD. Provisioning 20TB of bulk storage where only a small subset needs to be active at a given time is best for standard disks (plus tiering/caching). Purely sequential workloads are better served by spinning disks. And more than that, SSDs tend to do best outside of the disk form-factor. For the past year, I've been using PCIe-based SSDs to get around cost, performance and compatibility issues with traditional disk-based SSDs.


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