Adding a 3rd SSD... stripe it with the other two or use it alone?

Discussion in 'Mac Pro' started by VirtualRain, Jun 22, 2009.

  1. VirtualRain macrumors 603

    VirtualRain

    Joined:
    Aug 1, 2008
    Location:
    Vancouver, BC
    #1
    I've got a pair of 80GB X25M's in SW RAID0 for OS/Apps.

    I'm considering adding a third 80GB X25M with the intent of increasing my SSD storage to provide sufficient room for my active video editing project... e.g. it will be used as the scratch space for FCS.

    I can either add it to the existing RAID0 array, creating a 3-drive stripe for OS/Apps/Scratch, or I can simply install it stand-alone for scratch use.

    What would you do? Why?

    Cheers! :)
     
  2. Andrew Henry macrumors 6502a

    Joined:
    Mar 4, 2008
    #2
    I'd personally add it to the other two, can you imagine the speeds?
     
  3. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #3
    Add it. ;)

    1. Greater througput
    2. Increased capacity of the array
    3. Greater number of cells left unused on each drive for wear leveling. Helps if you have a high write usage.

    Number 3 helps mitigate the write cycle limits of flash from a 100% analysis of the failure rates (manufacturer data of the flash used), rather than say the 90th percentile that comes up with larger write cycle numbers based on the best cells (tosses the cells that only meet the minimum number of writes specified by the flash manufacturer).

    I hope this makes sense. :)
     
  4. VirtualRain thread starter macrumors 603

    VirtualRain

    Joined:
    Aug 1, 2008
    Location:
    Vancouver, BC
    #4
    I guess a better question would have been... Is there any reason not to stripe all three drives together? :D

    BTW, from what I've read elsewhere, I'll be nearing the max I/O capacity of the Intel ICH10R chip! :eek:
     
  5. lixuelai macrumors 6502a

    Joined:
    Oct 29, 2008
    #5
    IMO you should just get 2-3 Velociraptors for FCP. Usually for large projects the seek time is not paramount and transfer rate will be >300MB/s with 3 drives. Even regular 7200RPM drives in RAID should be good enough. Plus the extra space is probably more important.
     
  6. Andrew Henry macrumors 6502a

    Joined:
    Mar 4, 2008
    #6
    Considering he's already got 2 of the SSDs why in the world would he get Velociraptors? Especially considering the SSDs smoke those drives.
     
  7. lixuelai macrumors 6502a

    Joined:
    Oct 29, 2008
    #7
    SSD smokes it in seek. In terms of average read it is about twice as fast and 30% slower in average write. The cost of the SSD is about twice that of a Velociraptor. So if seek time is not paramount 2 Velociraptors will give about the same performance as an Intel SSD and you get more space. IMO keeping the 2 SSDs for OS and Apps where seek time makes the most difference and use HDDs for scratch or just project storage gives better bang for the buck without sacrificing much performance.

    But anyway the OP seems set on another SSD. In that case just RAID it. The major downsides of RAID is hardware failure and slightly increased seek. I doubt the SSDs will fail any time soon and the seek is next to nothing anyways.
     
  8. VirtualRain thread starter macrumors 603

    VirtualRain

    Joined:
    Aug 1, 2008
    Location:
    Vancouver, BC
    #8
    For my active project files, I only need about 20-40GB depending on the size of the project. I could almost get by with my existing dual SSD setup for OS/Apps/Scratch but I wouldn't be left with much free space which is not good for wear leveling. Adding another SSD would be just about right.

    I have one spare HD bay... (after my existing SSD's and my 1TB WD Black which I plan to use for archiving project files and daily active project backups).

    I considered adding another Black but I think for the extra couple hundred bucks, the SSD would be the better way to go.

    Backup strategy is...

    SSD project work >daily> 1TB project archive >weekly> 4TB NAS
     

Share This Page