Raid Questions.

Posted:
in Current Mac Hardware edited January 2014
I am thinking of setting up a hardware ( i know not to do software) raid on my brother's computer but i have a few questions.



It will be Raid 1 (redundancy). I hope you guys could help.



1) The data is already on one drive. When i setup a RAID, does it automatically copy the data that is already there? Or just the new stuff?



2) If one drive does die, would the other drive run the OS normally?



3) Also, if the one dies and i put in a new blank, would it copy (similar to Q1)



4)If i do use drives of different sizes, am i right that it will work just you will ony have the capacity of the smallest drive?



5)Could i set up RAID 1 with 3 drives? (added safety)



I hesitate to ask this now becuase i am really more concerned with the above questions, but what is a good raid controller for a Dual G5 1.8 with 2 gigs ram (i hate him becuase i am stuck with my 1.0ghz 12" powerbook and 768 ram)



Thanks for your help. I really, realy, appreciate it

Comments

  • Reply 1 of 1
    dobbydobby Posts: 797member
    I take it your not using and XServe and XRaid otherwise these questions would be pretty redundant.

    1. You can do it without destorying the drive but I would advise to do a backup beforehand.



    a) open terminal and su - root.

    b) diskutil list

    You need to get the name of the disk like disk0 or disk1

    c) diskutil enableRAID mirror disk0

    disk0 will be dismounted and should reappear after awhile (depends on size).

    d) now open DiskUtility and drag the other disk (disk1 or whatever) to the disk0 mirror to rebuild the mirror set.

    A rebuild takes ages. On my 2 200GB drives on my 2Ghz G5 (about 80GB data) I started the rebuild at 3.00pm and it hadn't finished by 5.00pm so I went home. It had finished in the morning tho.



    2.If one drive dies then the machine does run normally. In fact unless you check you won't know the mirror is down.

    3. If you put in a new disk then you need to use Disk Utility to release and readd the mirror.

    4. Not sure but I think you are correct, smallest size rules.

    5. There is no hot spare option (pity).



    Dobby.
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