Why SAS SSDs are better than SATA SSDs? Or...not really?

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I read a lot about the differences between Serial ATA, Serial-Attached SCSI and Near-Line SAS.

I understood that SATA drives are mainly used in client computers, enterprise archive storage arrays, tiered storage, etc. and SAS drives are used in enterprise environments where throughput and access speed is very important, maybe even more important than the capacity it gives.

It appears that the maximum rotational speed for SATA is 7200 RPM (rare exceptions are 10K) and SAS spins at 15000 RPM primarily. Apart from that, I know that SAS uses SCSI command set and the commands are re-arranged at the storage controller to optimize drive performance (due to seek time, I think) and allows for multiple hosts to control the drive without using any additional hardware.

As far as reliability is concerned, SATA HDD drive MTBF is said to be somewhere near 1.2 million hours and bit error rate about 1 bit/1 Pbit while SAS drive MTBF is 0.4 million hours longer and errors are ten times less common.

What are real benefits for choosing SAS SSD drive over SATA SSD drive? Are SAS SSDs are much more reliable too? Are they that much faster if we're not talking about rotational latency and head seek time anymore?

Thank you, guys, in advance!

Ashtray

Posted 2013-09-12T07:18:00.707

Reputation: 1 489

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I would have to say that all SAS SSDs are almost certainly enterprise SSDs. Enterprise SSDs have better characteristics. There are also differences between the ATA and SCSI control interfaces that make make differences in some cases. Have you read the wikipedia sections about Enterprise SSD? Have you reviewed spec sheets for enterprise SSDs? http://en.wikipedia.org/wiki/Solid-state_drive

– Zoredache – 2013-09-12T07:52:31.997

You're mixing up HDDs with SSDs. The latter use electronic memory such as flash. There are no moving parts, so rotational speed and head seek time doesn't apply to them – Zerobinary99 – 2013-09-12T09:45:37.437

@Zerobinary99, I said that same thing... – Ashtray – 2013-09-12T09:54:07.363

Answers

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Well, the answer to any good question depend on the how you plan to use it.

  • In theory SAS is better than SATA
  • SAS is designed for Server Environments.
  • It has dual porting, and can fail over to another server if goes down.
  • In practical life, SAS has no real advantage at Home.
  • If you a hobbyist and your building a cluster, then it will help you.

  • Another advantage is it runs well in a 24x7 environment.

  • Speaking about speeds and latency; You won't really notice the difference unless you have two or more disk intensive activities running at the same time.

aliasgar

Posted 2013-09-12T07:18:00.707

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Asked: 2013-09-12T07:18:00.707

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Active: 2015-04-02T14:33:12.577