setting upp 2 SSDs in a new MacPro

[Jann Lipka]

I have ordered a 6 core MacPro  24 Gig RAM and want to put a couple of SSDd rives in it -

I'll buy some SandForce SSD like OWC ( unfortunately no Sweden reseller )  or Corsair F240 or OCZ vertex 2.
Hopefully 2 x 200Gig per Drive .


From what I see what Digiloyd  recommends making RAID O  stripe volume   and 2 partitions of it
Boot 180 Gig and second partition 280 scratch + some files  would make some sense

Versus

Just one big ( SSD wise ) Raid 0 Volume  ... for all fast needs ( frequently backup to another HD )

OR  :


Alternative would be one SSD for Boot and one for scratch. No Raid volume JBOD only 


Any suggestions for configuration  ? - my work is PSCS5 , Lightroom, and some PTGui .....

[ErikKaffehr]

Hi,

I guess that it may matter little. The main advantage of SSDs is probably seek time. Making a stripe would allow for faster transfer. Having big start volume may be easier use optimally making partititions for scratch may be better for maintenance.

As read/write operations don't involve head movement I'd suggest layout issues matter little.

Best regards
Erik

[Jann Lipka]

OK - I'll start with Raid 0 / partition in two  and see .

[loonsailor]

There are three possible advantages to RAID.  One is speed, but, as Erik noted, with SSD you probably won't gain much there.  The second is redundancy, if you use Raid 1 or 5.  With only two drive, though, you'd lose half your capacity for the redundancy.  If you're backing up regularly, that's probably not worth it. 

The third advantage is that you can address both drives as if they were one larger drive.  If you think this will be more convenient for you, then RAID is one good way to accomplish it.  There might be others (a virtual file system) but I'm not sure what else is available on mac.

[Jack Flesher]

Note that many SSD's do NOT like to RAID!  SO be sure the ones you buy are RAID certified.  (You'll note that even OWC offers two different series of their SSD's for this very reason.)  

Re your configuration.  I tested a pair of OWC RE's in R-0 as dedicated boot, dedicated scratch, and partitioned as Boot/Scratch as you are suggesting.  Bottom line was there a whopping 1 second gain on boot and app launch and zero detectable gains on anything else with the R-0 boot and OS set up.  The dedicated R-0 scratch set-up faired even worse -- zero gain on heavy CS processing that forced scratch over a single SSD.  Moreover, my existing 4x spinning drive R-0 stripe with Scratch partition was still faster than the SSD by a about 10%.  SSD R-0 boot/scratch was no different than SSD R-0 boot and single SSD scratch.  So my bottom line reco, at least for now, is that a single SSD for boot plus a single SSD OR 4x spinning R-0 for scratch is probably your best option.    

[Jeremy Roussak]

As Jack has said, the combination of RAID and SSD isn't always a happy one. Apple say their RAID card isn't compatible with SSDs (at least, with their SSDs), as no doubt you've noticed.

Jeremy

[Jann Lipka]

Jack - thanks for you real life observations.
I'm slightly reluctant to Raid 0 , I have been using it several years ago - and there
was sometimes problem with it .

Raid solution is just one more thing that can go wrong , and I try to have  more simple setup.
( If the speed advantage would be substantial I would go with striped disks anyway :-)

I'll order OWC's RE drives .