G5: To RAID or Not to RAID . . . Dissimilar HD?

Discussion in 'PowerPC Macs' started by DetroitMacJack, May 2, 2010.

  1. DetroitMacJack macrumors newbie

    Joined:
    May 1, 2010
    #1
    Hello,
    I have read that it is "a shortcut to disaster" if I do a RAID0 (or any other RAID for that matter), if the Hard Drives are dissimilar. I have the original HD 149GB (now 5 years old), and have bought a new 1T HD, and was planning on setting them up as a striped RAID0. Is this a bad idea? Should I purchase a second 1T HD and do a RAID0 or RAID1 setup instead?

    Thanks for any advice, Jack

    PS. G5 specs below
     
  2. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #2
    Technically there is no requirement for using two identical hard disks with RAID0, in your case however it wouldn't make any sense at all.

    If you stripe two disks, the Array size you'd get is defined by the smallest disk, which means that you'd get 2 x 150GB out of your two drives.
    The 850GB that are left on the 1TB drive won't be used.

    So yes, get another 1TB drive!
     
  3. DetroitMacJack thread starter macrumors newbie

    Joined:
    May 1, 2010
    #3
    Transporter,

    I thought a striped RAID0 simply reads both HD as one HD, while adding to the total storage space. From what I've read, it sounds like you are referring to a RAID1, which mirrors the main HD, which does as you described. Forgive me if I sound confused, as I am.:confused: Thanks for taking the time to un-confuse me.

    Jack
     
  4. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #4
    Please take a look at the Wikipedia article on RAID. Hit me!

    That should give you a very good first insight into RAID.

    With RAID0 your OS indeed treats two (or more) hard discs as a single one, but striping doesn't mean that capacity of the drives are simply added.
    RAID0 out of two drives stripes (that's there the name comes from :p) the data 50/50 on two identical sized partitions. As I said, the remaining 850GB would remain unused.
     
  5. dazey macrumors 6502

    Joined:
    Dec 9, 2005
    #5
    The above is not entirely true. It is true if you RAID using apple disk utility. If you use softraid you can RAID partitions. You can take a 150GB disk and a 1TB, Stripe raid the 150GB and the first 150GB of the 1TB leaving the rest as an individual disk. As an example, I RAID the first segments of two drives to use as a fast scratch volume and leave the rest for storage (not wanting to have greater chances of data loss).

    I will add however, that a 150GB disk is A)past its use by date b)slow compared to a current drive. Stripe raiding it makes the chances of losing data higher.
     
  6. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #6
    Hello,

    I've yet to see any real advantage to using softRAID. Apple's Disk Utility can do exactly what you describe: I've used it myself to build the two soft RAIDs I have on my mac right now.

    Loa
     
  7. DetroitMacJack thread starter macrumors newbie

    Joined:
    May 1, 2010
    #7
    Hi All,
    First, a big thanks for your time! All your advice has been extremely helpful. It sounds like the best thing I could do is purchase a second 1T HD, and run a more secure storage system, and I will plan on doing that.

    Next question, as I am a first timer into the 'open up and personally upgrade-r', I'm now thinking, which is the best way to install two new HDs, and save/transfer the data from my original 149/160 HD to the new disc/s. Here is another question I hope you'll be able to help me with (and, I think this thread will also be extremely helpful to others wanting to do the same):

    1. Do I: first install one of the new HDs, transfer data from original, or, ??? . . . then install second new HD, and RAID0/1 them(I believe RAID1 is safest in case one HD dies? (thanks for the Wiki link!) Though, RAID1 will max HD storage at 1T, correct?

    Thanks, Jack
     
  8. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #8
    The initialization process (creating the RAID), will wipe any data on the drives used to create the array, so copying data first is useless, and a waste of time.

    Assuming you can utilize the 149GB disk after the array is created (read), you then copy the data from it to the array (2x 1TB disks) assuming that's what you want to do.

    If not, you'd need to find a way to gain access to it once the array is created, whether it means transferring data to another source, external enclosure, ....
     
  9. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #9
    It's very rare that people hesitate between RAID 0 and 1: they're *very* different beasts. RAID0 is for performance, and RAID1 is for redundancy.

    But keep in mind that redundancy is *not* a back-up solution at all. Regardless of which RAID you decide to build, you'll need a good back-up strategy that is not involved in your RAID.

    Loa
     
  10. DetroitMacJack thread starter macrumors newbie

    Joined:
    May 1, 2010
    #10
    Best process gettin data transfered from Old HD&2 new HDs installed wt 2 HD slots?

    Best process gettin data transfered from Old HD&2 new HDs installed wt 2 HD slots?

    Hi,

    I have 2 new HDs (each 1T) uninstalled, and I have my old HD (160 gigs) currently residing in one of the two slots in my G5. Any ideas on the best way/process to get the data transfered from the old HD to the new ones, leaving my two slots filled with the 2 new drives AND my data from the old HD transfered and intact, with a RAID0 setup?

    OR, are there any other suggestions on a good setup with the 2 new HDs??

    I'm open to suggestions.

    I always back-up on external HDs, so, is their a need for me to worry about setting up a RAID0??

    I'm doing video processing for DVD release.

    Should I just max out the 2x1T gig HDs and not worry about a HD failure??

    All Suggestions welcomed!!

    Thanks, Jack
     
  11. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #11
    Hello,

    Well if you have an external back-up, just make:
    1) a complete back-up of your 160GB drive,
    2) remove it and replace it with your two 1 TB drives,
    3) setup your RAID0 in disk utility
    4) and restore from your back-up.

    Your RAID0 will show up on your desktop as a single, regular drive. You should treat it as such: once setup, RAIDs behave just like any HDD (only faster).

    As for drive failures: they could happen as soon as you set up your RAID0 or in ten years. Nobody knows. Regardless of the fact that you use a RAID0, you should always back you data very regularly. So actually using a RAID shouldn't matter.

    Loa
     

Share This Page