[mduell]

I haven't seen this mentioned here, but I was looking for info on SAS drives in the Mac Pro (since the Xserve supports them) and found out that the new $1000 RAID card for the Mac Pro also adds SAS support. SAS is Serial Attached SCSI which uses the SCSI protocol over a SerialATA connector. There are some screaming fast SAS drives out there (up to 300GB/15000RPM) which leave SerialATA drives (even the beloved Raptors) in the dust particularly in the area of operations per second. See StorageReview.com's review of the Raptor and Cheetah to compare the results.

Good news for ninahagen, SierraDragon, and all the other performance addicts out there.

[MallyMal]

Very interesting. Also, trancepriest is a member here.

[ninahagen]

Originally Posted by mduell 

I haven't seen this mentioned here, but I was looking for info on SAS drives in the Mac Pro (since the Xserve supports them) and found out that the new $1000 RAID card for the Mac Pro also adds SAS support. SAS is Serial Attached SCSI which uses the SCSI protocol over a SerialATA connector. There are some screaming fast SAS drives out there (up to 300GB/15000RPM) which leave SerialATA drives (even the beloved Raptors) in the dust particularly in the area of operations per second. See StorageReview.com's review of the Raptor and Cheetah to compare the results.

Good news for ninahagen, SierraDragon, and all the other performance addicts out there.

That absolutely rocks. The big question that raises is how many we can stuff into the new MP case. 10 would be ideal. (lol) Is there any adaptor/bracket that will allow the use of SAS drives inside the current SATA bays? Mark, aren't you going SAS too? I have to believe you are planning something here.

Also, SAS are superior to SATA, but what about IDE... I just wonder why high-end RAID arrays wouldn't use SAS, and opt for IDE instead.

[newtech]

HELLO!!!....MC FLY!!!..... SAS uses the same connector as SATA, only the command structure is different.

[mduell]

Originally Posted by ninahagen 

That absolutely rocks. The big question that raises is how many we can stuff into the new MP case. 10 would be ideal. (lol) Is there any adaptor/bracket that will allow the use of SAS drives inside the current SATA bays? Mark, aren't you going SAS too? I have to believe you are planning something here.

Also, SAS are superior to SATA, but what about IDE... I just wonder why high-end RAID arrays wouldn't use SAS, and opt for IDE instead.

As long as you get 1" thick SAS drives, they should fit just fine in the existing bays. SAS is tempting but I need capacity/bandwidth moreso than I/Os, so I'll stick with big SATA disks.

IDE is older and slower than SATA; it doesn't support NCQ and doesn't have enough bandwidth for the latest 1TB drives.

[tadd]

SAS drives have many other cool features. They use a globally unique ID (GUID) like ethernet MAC addresses and can be networked via the SAS bus. You can have SAS expanders that let multiple arrays of drives be connected in place of one array. The channels may be bundled to get 4x the speed. Each SAS drive actually has two serial connectors, for redundancy not for speed. If you inspect the socket on the back of a SAS and SATA drive you will notice 4 more contacts on the SAS drive in between the power connector and the SATA data connector (note: They are on the opposite side of the plastic from the SATA connections). A SAS backplane connector will contact power, data and alternate data all at the same time.
If you have a proper SAS backplane it may be connected to two different SAS RAID cards at the same time for automatic failover.
I'm not sure if both RAID cards are 'hot' at the same time. I didn't get that far. I suspect they are since the "PHY"s are both addressable (on the back of the SAS drive) as separate GUID addresses.