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I am pondering a difficult question. Should I choose SAS or SATA? I ask, because I building an IO intensive application, and would like to know if the benefits of SAS outweigh those of SATA (enough to make it worth the dosh).

I will be placing many relatively small files on these drives, and reading / writing somewhat randomly. I am mindful that in the past, SCSI would usually destroy IDE drives, from a random IO perspective, but IDE was much cheaper. Now I have to choose among their latest incarnations, that of SAS and SATA, but haven't found much information on the internet. with the general exception of various sites saying that they perform somewhat identically (no real details under what conditions).

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The real bottleneck for random access is the drive, not the interface. If you can afford it, get SSD(s) and stop worrying about the interface. – Dennis Nov 18 '11 at 2:05
Well, I've run into a problem of cost / capacity there. > 500 GB SSDs tend to be rather expensive, I'm afraid. – user978122 Nov 18 '11 at 2:15
up vote 1 down vote accepted

The controller is by far less important than the drive itself.

  • A 7,200 RPM drive performs up to 100 reads/writes per second.
  • A 10,000 RPM drive performs up to 150 reads/writes per second.
  • A 15,000 RPM drive performs up to 210 reads/writes per second.
  • The OCZ Vertex 3 (for example) performs up to 65,000 writes per second (and up to 55,000 reads).

As the speed increases, so does the cost.

Depending on what data you store (and what for), you could also consider a SSD cache. That way, you need only a small SSD for the files that get accessed frequently.

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Already have the SSD. The problem is one of capacity (the SSD is going to get eaten up quick). – user978122 Nov 18 '11 at 4:35
+1: Both interfaces can more than keep up with today's SSDs. – surfasb Nov 18 '11 at 9:27
@user978122: How big is the SSD you already have? What are you using the computer for? – Dennis Nov 18 '11 at 10:52
128 GB SSD. Working on a genetic program, which will create many (potentially more than my filesystem can handle) 4 KB files. It will read the files linearly, but the files themselves may be placed somewhat randomly around the disk, hence my caring about a relatively large hard drive that can handle intense IO. Even using the SSD as a cache is more of a band-aid than a solution, because I still need to transfer those files off to free up space, and the SATA II media drives take forever to copy them off. I'd like to set it up so that it goes SSD -> SAS or SCSI (something larger) -> Media Drives – user978122 Nov 19 '11 at 5:10

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