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Lately I have been seeing people online and their followers making NFS servers with SATA SSDs for VMware Datastores. This enraged me! SATA is half duplex and SAS is full. A 15k SAS at 6Gbs with a 6Gbps raid card would blow away a SATA SSD when the server has multiple VMs running on it. So the question, did I miss something? Am I wrong? Or are these people just misinformed?

SmarterThanYou
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You missed two things:

  • 15k (and partly 10k) drives were almost killed by entreprise SATA SSD;

  • HDD IOPs are strongly limited by random access, rather than interface bandwidth.

Modern high perf server are generally build around SATA + NVMe, unless SAS multipathing is required (ie: a JBOD connected via SAS to multiple head nodes).

shodanshok
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    That pretty much is it. Modern SATA is not the limiting factor because it is way high enough for the pathetic IOPS a spinning disc gives (compared to SSD). – TomTom Feb 09 '20 at 08:29
  • I like the detail that you wrote enterprise SSD, which in my region currently cost more per gig than a SAS drive. I see too much bad setup with consumer SSD, which are not done for the fiability to be always on use. – yagmoth555 Feb 09 '20 at 17:30
  • One third point - price. SAS drives come with a premium price. – Criggie Feb 09 '20 at 19:04