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Discussion in 'Mac Pro' started by cube, Aug 5, 2010.
The Mac Pro is really missing SAS. There are 6Gbps 15000RPM disks at very reasonable prices.
They are loud, hot, low capacity, expensive and annoying. I have many in servers and wish I didn't.
Well, if you don't like those, you can put cheap 7200RPM drives and you still have advantages over SATA.
Apple's never implemented SAS (let alone a built-in SAS RAID controller, such as an LSI 1064) as can be found on other enterprise grade systems, so it's not unreasonable to expect this to continue to be the case.
You'd need either an HBA (Host Bus Adapter that's non-RAID) or RAID card to support SAS disks (currently, ATTO is the only company I've seen with 6.0Gb/s SAS gear).
Yes, but can you boot from them and how do you connect the ports to the bays?
Apart from the Xserve.
#1 would be the additional error recovery and reporting support.
Which I need for (in a desktop machine)?
I don't know I just don't see the point of buying expensive drives that won't give me any speed increase, nor a plus in reliability compared to standard 24/7 drives.
Is error recovery really the must have in desktop drives?
Well, Macs were downgraded from SCSI to ATA, there's no reason to be stuck there when you can use the same port.
At the time, it was more of a lateral move.
Not natively from what I can tell (chipset or any additional semi's on the board). It's an add on:
From the main information page.
From the Buy page.
Check out the Buy page on either the Quad or Octad page. BTW, check out the SAS Drive Kit page for a bit more info.
They are faster than SATA.
If you're running an environment of high writes of small files (random writes), both the faster platters and servo motors will certainly be a better solution in terms of performance than SATA (servo moves the heads). It's also better than SSD for this type of usage due to the write cycle limits of Flash (it's why the use SLC in enterprise grade SSD's, which are quite expensive).
The additional error recovery capability is also more desirable in RAID.
It all comes down to what you're doing. So it will matter for some, but not others.
I'm try to decide whether to get SAS or SATA 2TB HDs for a 2010 MacPro. Newegg sells a Seagate Constellation SATA [$299] and Constellation SAS [$330]. So price isn't a factor.
Each has a drive speed of 7200rpm
SATA drive has 64MB Cache; SAS 16MB
SATA is 3Gb/sec; SAS is 6Gb/s
SATA warranty is 5/5; SAS is 3/3 [Seagate says both are "enterprise class"
MTBF for each is 1.2 million hours
I don't know how to trade-off thruput [if that is the right term] and cache. SATA has better cache [and warranty]; SAS better thruput.
I'll be using the HDs in a 4 or 5 disc RAID 5 [SSD for OS & Apps] with an Areca raid card [either 1880 or 1680]. HD reliability is important to me.
Any advice or suggestions?
read somewhere that the current apple raid controlers have SAS too
Check out the throughputs for the two different models. But based on the smaller cache and lesser warranty (big one IMO, as they almost certainly share the same mechanical parts), I'd probably go for the SATA versions if it were me.
SAS however does have some advantages for RAID recovery. But the Areca cards I've used do well with SATA (I've dealt with SATA disk failures on 12x1ML and 1680 series cards). Just had to swap in new disks, and let it rebuild (I prefer not to try and use the array while the rebuild occurs as a means of reducing disk stress during the process, in the event others are weak).
Between the 1880 and 1680 series, you'd be better off with the 1880 series IMO, as it's better suited for SSD's (future use due to 6.0Gb/s compliance), and the performance data available shows it's faster than the 1680 counterparts for very little difference in cost (i.e. ~$100 more for the 1880 model, which I consider well worth it, as the hardware can last longer = transferred from one system to another as needed).
Yes they do (SAS controllers support SATA disks, which is nice). I was referring to the logic board (not having to add a PCIe based card in order to provide SAS support).
Other boards or systems will use additional 3rd party semiconductors soldered to the motherboard, such as Marvell or LSI chips in order to provide built-in SAS capability.
There is a fix for that. Its known as "buying a SAS PCI-E card".
nanofrog. Thanks -
So why do you care if they get loud and hot? They are in a server and servers runs in cool datacenters.
SAS is a replacement of SCSI and SCSI disks are fast, can perform many operations at once, reliable and if you run out of capacity you just get some more..
If you really have unlimited budget get a FiberChannel SAN and at FC card for your mac pro and you can get screaming fast storage where you can run as many SAS disks you want. Would cost you about $50.000 but what wouldn't you do for loading Apple mail quicker....
The dev enviroment is in the same room with me. Its annoying.
If you're running SAS disks, you can run longer cables to get it further away from you (up to 10 meters). Much better than SATA, as it's limited to 1 meter for passive signals.
So your running servers as a dev environment in the same room as yours? Well that's just stupid. If I where you I would have got a workstation as a dev server instead and the problem would have been solved.
If I read SAS I think of these guys:
I think this is more appropriate!
(Let's not let the Yanks think our boys are a bunch of pansies! )
Love the avatar BTW