New RAID, but which type?

Discussion in 'iMac' started by Utterchaos23, Apr 30, 2013.

  1. Utterchaos23, Apr 30, 2013
    Last edited: Apr 30, 2013

    Utterchaos23 macrumors member

    Utterchaos23

    Joined:
    Mar 20, 2011
    Location:
    Brighton UK
    #1
    Hi All,

    Ok.. I have a nice collection of external HDD and I think i can improve my general iMac performance by using RAID... but in what configuration?

    I have about 1.5 gig of data, some of which could be "quick access" and some library only so slow access is fine.

    I have:
    250g Lacie firewire
    1TB Lacie firewire
    2TB Lacie firewire
    2TB USB
    4TB USB3 (although I have no USB3 ports... just the way the drive came!)

    I'm planning on using....

    250g as an off-line clone of my iPhoto Library

    Via my Airport Extreme and stashed in safe places round the house:
    2TB USB as - clone of iPhoto Library+ clone of home movies + 500mg partition as iMac HDD clone.
    4TB USB as a time machine.

    So that's me backed up.

    Then for iMovie, Photoshop, Logic etc I want to use:
    1TB Firewire + a 1TB partition of the 2TB Firewire as a RAID for speed.
    The other 1TB as slow library storage.

    but what RAID do I use?

    I want to use stripped for speed but worry about reliability? I'f I'm fully backed up.. am I worrying about nothing? Also, stripping apparently has to be identical disks? Although I went though the first bits of creating the set (without pressing "GO") and it seemed to accept the Disk + Partition as a set?

    Or, to be safe, is mirrored better?

    Also... will the resulting Stripped RAID be quicker to access than my internal SATA?

    Interested in your thoughts/experiences....

    J

    ________________________________________

    Ok... Update.

    I have freed up my 1TB and created a RAID0 set with that and 1TB of my 2TB drive.

    It works flawlessly and offers absolutely no speed increase whatsoever!

    The "slow" half of my 2TB gets 60-70m/s from Drive Speed Test and the RAID drive gets exactly the same?!?!?

    What's that all about? - Is it just because my Mac is ancient? My internal only gets 70-80 as well...

    J

    P.S. - Am I talking to myself here :p
     
  2. Bear macrumors G3

    Joined:
    Jul 23, 2002
    Location:
    Sol III - Terra
    #2
    Raid 0 requires identical partition sizes, not identical disks. although having disks being identical gives the best performance. The down side of raid 0 is that if one disks fails, you lose access to all your data. In your case accessing the other 1 TB partition would impact performance of the raid 0 set.

    Raid 1/mirroring allows you to keep running if one disk fails. Mirroring improves read speed only where raid 0 improves both read and write speed.

    Now in your case since everything is on one Firewire port, that will be an impact on performance as well, I'd say mirroring would be your better choice.

    As for what would be better internal drive versus firewire, it depends on what's going on on both of them. With OS X on the internal drive, even if the firewire is slightly slower, it could still wind up bring faster since you're now reading data off of 2 different ports.
     

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