9

I have a Supermicro X8STi-F motherboard and would like to know if I can use SAS drives on it. I am not concerned with RAID right now, just if the drives will work. Or does the fact the motherboard is SATA imply that it only handles SATA drives?

Thank you kindly.

10

For SAS, the two connector segments (power and data) were merged, which makes it possible to attach a SATA drive to a SAS controller using the continuous(SAS) connector known as a SFF-8482 connector, but you cannot hook up a SAS hard drive to a SATA controller.

Wikipedia reports

3.0 Gbit/s drives may be connected to SAS backplanes, but SAS drives may not be connected to SATA backplanes

I assume this is a reference to servers that support both drives. There are signaling voltage differences for sure so even though the Wikipedia has no detailed reference, it is not possible.

5

This might also help those who want certainty and more info:

http://storage.microsemi.com/en-us/_whitepapers/tech/sata/sas_sata_unprlcompat.htm (from early 2000s)

[T]he SAS interface will also be compatible with lower cost-per-gigabyte SATA drives, giving system builders the flexibility to integrate either SAS or SATA devices and slash the costs associated with supporting two separate interfaces.

The SAS connector is [..] form-factor compatible with SATA, allowing SAS or SATA drives to plug directly into a SAS environment whether for mission critical applications with high availability and high performance requirements or lower cost-per-gigabyte applications such as near-box storage.

SATA connector signals are a subset of SAS signals, enabling the compatibility of SATA devices and SAS adapters. SAS drives will not operate on a SATA adapter and are keyed to prevent any chance of plugging them in incorrectly.

[T]he similar SAS and SATA physical interfaces enable a new universal SAS backplane that provides connectivity to both SAS drives and SATA drives [..]

SAS consists of three types of protocols, each used to transfer different types of data over the serial interface depending on which device is being accessed. Serial SCSI Protocol (SSP) transfers SCSI commands, SCSI Management Protocol (SMP) sends management information to expanders and SATA Tunneled Protocol (STP) creates a connection that allows transmission of the SATA commands. By including all three of these protocols, SAS provides seamless compatibility with [...] SATA devices.

Also these example product spec:

https://www.attotech.com/products/adapters/sas-sata-raid and http://www.avagotech.com/products/server-storage/raid-controllers (LSI-as-was)

"ExpressSAS 6Gb/s SAS/SATA RAID Adapters provide high performance data protection to direct attached SAS and SATA JBOD storage [..]"

"Support for 6Gb/s and 3Gb/s SATA and SAS drives to balance cost and performance"

3

Shorter version:

SAS on SATA Backplane = NO.
SATA on SAS Backplane = Mostly YES.

2

SAS and SATA use different signaling voltages. Using SATA on a SAS backplane will function but the opposite will not, as a consequence of the voltage ranges.

-1

well I have SAS on my SATA ports but they drop out after a few hrs ( SATA backplane modded with plastic chock removed )

so I guess there is a bit more to it than the physical connectors

-2

You have it backwards, you can use SAS on SATA, but not SATA on SAS, you can buy adapters that work just for this.

  • 6
    Actually, you have it backwards. SAS only connects to SAS. SATA can be attached to either SATA or SAS. (I have SATA laptop drives attached to my SAS server right now) – Ricky Beam Jan 27 '14 at 21:47

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