There's only one SAS, right? Serial attached SCSI?

The female connectors:

SATA2 looks like: ------------| |-------

And SAS looks : ------------+-+-------

For me, the SATA2 male connector looks like it has little corners in the middle that would prevent it from sliding into SAS, which doesn't have the little gap to allow the corners in. Is this correct?

  • You can push a USB-A plug into an RJ45 socket.. Not a lot will happen, though. – Tom O'Connor Dec 15 '11 at 23:28
  • Now I've got it: If your (SATA) female connector has what works like a bumper in the middle, you can push in a two parted connector (SATA), but not SAS, which is a un-gapped thing. Thanks everyone! – isync Dec 15 '11 at 23:28

It works. SATA discs are compatible with SAS. I have tons of them in SAS backplanes. Work like a charm.

  • Yeah, SATA is pretty much a subset of SAS protocol, as well as those connectors are. You cannot use advanced SAS features with SATA drives, but as long as your only concern is connecting SATA drives to SAS controller and/or backplane, you're just fine. – Fox Dec 15 '11 at 23:29
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    Note: SAS supports something called STP (SATA Tunneling Protocol) where SATA commands can be sent over SAS HBAs and Expanders. This extends SAS's capabilities to communicate with SATA Storage Devices. It's true that SATA is based to a degree on SAS, but they're not natively compatible (other than STP). – Chris S Oct 3 '13 at 18:03
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    Well, we can discuss semantics here. As STP is aprt of the SAS protocol it is QUITE native ;) – TomTom Oct 3 '13 at 18:10
  • I've heard someone say you need SAS drives or "Enterprise SATA" - is there a physical/protocal difference between "Enterprise SATA" and just plain "SATA"? I always figured it was just a quality difference. – Adam Nofsinger May 9 '14 at 16:34
  • This pretty much is it. Enterprise SATA is also called nearline - those are generally SAS drives with a SATA interface (i.e. you get the same drive also with a SAS interface) and / or specially made mid quality drives - enterprise production grad, lower speed for storing stuff, not running databases. Seagate for example has such drives. – TomTom May 9 '14 at 16:57

Yes, difference: SATA devices contain a gap between the power and the data connectors, while the SAS devices do not. Meaning: You can connect a SATA device to an enclosure that supports SAS and SATA, but (hopefully;) not the way around.


You should install an interposer board between HDD and the backplane in case you have problems. See: http://www.knowledgetransfer.net/dictionary/Storage/en/SATA_interposer_board.htm

  • Interposers are mainly meant to provide Dual-Porting for SATA disks. Dual-Porting means that two host controllers can be attached to one disk, so if one host controller fails, the disk can still be accessed by the other one. – Klaws Dec 1 '19 at 13:10

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