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 throughput [if that is the right term] and cache. SATA has better cache [and warranty]; SAS better throughput.
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?
Thanks.
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).
read somewhere that the current apple raid controllers have SAS too
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.