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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Desktops > SAS for start up disk on new Mac Pro?

SAS for start up disk on new Mac Pro?
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Jupeman
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Join Date: Feb 2003
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Jan 9, 2008, 10:12 AM
 
So I spec'd my new Mac Pro with the RAID card and am debating how to set up the system. Should I/can I put one SAS drive in as the boot drive (I assume this is faster than a raptor) and then run 3 SATA disks in RAID 5 in the remaining three bays?

**never mind, I just read that you can't mix SAS and SATA**
Lots of Macs in the house...
Mac owner since 1985
     
CatOne
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Jan 9, 2008, 01:42 PM
 
So go with 4x300 GB SAS drives ;-)
     
SierraDragon
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Jan 11, 2008, 08:27 PM
 
Originally Posted by CatOne View Post
So go with 4x300 GB SAS drives ;-)
I am debating that vs. 4x1 TB SATA with 2 of the drives in a RAID 0 array. The SATA provides 3x the capacity at similar price. At Expo I will try to find out about real world throughput comparisons. I.e., do I really need 250 MB/s or will the eSATA RAID 0 be "good enough"? My gut tells me I need the additional capacity more than I need the marginal throughput increase of SAS. Larger drives mean less full, and full drives are slow...

Most likely I will end up with some third party drives but I will not know until after Expo.

-Allen Wicks
( Last edited by SierraDragon; Jan 11, 2008 at 08:35 PM. )
     
mduell
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Jan 11, 2008, 09:32 PM
 
RAID does nothing for latency and not that much for I/Os.

If you just need bandwidth, go with big SATA drives. If you need low latency and/or lots of I/Os, go for high-speed SAS drives.
     
svtcontour
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Jan 12, 2008, 12:26 AM
 
Not sure how relevant this is to this conversation, but my main computer at home is a winPC box with a 74GB 15K U320 SCSI drive and a 36GB 15K SCSI drive as swap. My data is stored on a pair of 250GB SATA drives.

I've used many computers and I can honestly say that I have not encountered a SATA or IDE based system that felt the same especially when juggling a few disk intensive tasks at the same time.

I think raw disk speed (linear read speeds) are much less important in day to day usage than low seek times. Also not sure why, but my second PC which has a lowly 36GB Quantum Atlas 10K III drive and a P4 3.0Ghz cpu feels like it will murder the Core2 Duo 1.86 system I run at work that has a 74GB Raptor HD. Much more responsive.

So my conclusion although might be wrong but its still mine is that SCSI / SAS intelligence is probably goign to help out when the system is being hammered during heavy multitasking and low seek times way more important than bandwidth.
     
   
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