Software RAID 5 on Leopard?

Discussion in 'macOS' started by BlackDan, Jun 26, 2007.

  1. BlackDan macrumors 6502

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    #1
    A quick question to all you developer's out there that got a hold of a Leopard-copy.

    I would like to change my current X-serve setup. Unfortunately Disk Utility does not allow me to do RAID 5. Just RAID 0 or 1 + Concatenated (=JBOD). Did this change in Leopard?

    Silly thing is I have a 3x300Gb config and RAID 5 (1X600Gb) just makes a lot more sense than 1x 300GB+ 1x300GB in mirror...

    Thanks for having a look guys!

    /me prays the answer is yes :D
     
  2. BlackDan thread starter macrumors 6502

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  3. wrldwzrd89 macrumors G5

    wrldwzrd89

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    #3
    I know there are plenty of people that are running the Leopard beta here, but far fewer, if any, have Leopard Server and an Xserve (which is what I'm guessing you have). I envy you, I want one of those bad boys but can't really afford both the ADC Select membership fee AND the price of an Xserve:(
     
  4. BlackDan thread starter macrumors 6502

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    #4
    Well, it's not mine, it's the company's. :cool:

    On tiger the Disk Utility is basically the same on the client as it is on the server. I guess the same will be true for leopard. I'd be happy with just a hint as to what the client's version can do.

    With Mac Pro's offering up to 4 drives built-in. Raid 5 would be soooo nice...
     
  5. pengu macrumors 6502a

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    #5
    um there used to be a dedicated card for raid in xserves?

    im not aware of ANY OS/app ANYWHERE offering software based RAID-5.

    ZFS/Z-RAID would give you what you want (plus other goodies) but it looks less and less likely that it will be stable/included in the initial release of 10.5.
     
  6. BlackDan thread starter macrumors 6502

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    #6
    Well, Apple offers the X-SAN, but I don't need all that :eek: . We only have 1 X-serve (everything else is HP) and it serves only a small amount of end users. All I want is to have the 3 internal disks to have decent redundancy. Software RAID is the way to go in this case, but as long as the choice is between RAID 0 and 1 it's not very helpful as 1 disk will always be "unprotected" :(

    Also, RAID 5 in software is certainly available on WINDOWS and LINUX and it works perfectly (in fact I've had as good or even better experiences with software RAID 5 than I have with hardware RAID 5) ;)

    ZFS will be too long a wait, I guess...
     
  7. pengu macrumors 6502a

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    #7
    um. XSan isnt software RAID. they perform VASTLY different tasks.

    and out of interest sake, what are the software implementations?

    also, it seems the PCI-X RAID card was for G5s only. :confused:
     
  8. BlackDan thread starter macrumors 6502

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    #8
    You mean implementations on windows/linux?

    Well, Windows has this integrated in the disk management console. Convert your disks to a dynamic disk and then select the type of RAID you want. Whether it's 0, 1 or 5. Supereasy.

    On linux you have LVM. Basically the same thing.

    On Apple (with the Disk Utility) you have only RAID 0 and 1 available... that's my problem ;)

    Saying that software raid and hardware raid perform vastly different tasks sounds a bit odd to me. They both deliver data redundancy at a certain cost.

    Anyway, that's not the point. I know I can't have hardware raid on the "basic" x-serve. (It's a 2x2ghz G5 BTW, not the shiny new Intel. we've been running it for 2 years now) It hasn't been a problem (yet) 'cause I replicate the data on the drives anyway (more than once even).

    But I feel the need to improve on the current situation, by moving the data redundancy from replication (to a different drive, which, in case of failure would take a while to re-replicate) to redundancy on the 'disk-level' (which, means, that in case of failure, performance may be down, but I need 0 time to restore the functionality/available data).
     
  9. pengu macrumors 6502a

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    #9
    ok. didnt know ms supported it in software.

    according to wikipedia LVM CANNOT offer RAID5 functionality, and instead there is a software raid driver..

    anywho. um..
    why can't you use apple's hardware raid card?

    b) you missed my point. XSan is NOT SOFTWARE RAID. it is a STORAGE AREA NETWORK. that means two or more people can access the same file at the same time. it also gives great performance. but it still needs something to provide the raw disk speed/data redundancy.
     
  10. BlackDan thread starter macrumors 6502

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    #10
    The hardware raid card you refer to, is that the Fibre-channel card? (I'm unaware of any other) I believe this card is only used to connect your x-serve to an x-raid... no?

    Anyway, this is not a matter of life and death. As I mentioned before, the machine has been running for 2 yrs now and I have multiple backups in case it fails. I was just wondering if Leopard would let me improve things... To me (and to the company) that would be worth the cost of an upgrade to Leopard server...
     
  11. mauldus macrumors newbie

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    Jun 27, 2007
    #11
    The Fibre Channel card is not a raid controller. It simply presents the OS with the drive configurations that the Xserve Raid is setup for. The Xserver Raid box has the RAID Controller inside of it to manage the drives and parity. The Fibre card just connects your motherboard to the raid controller.

    Even though I'd rather have a hardware RAID solution, it would be nice if Leopard supported software RAID 5. I don't see what the big deal is other than keeping it simple for end users or wanting power users to buy the Server edition. Linux has been doing software RAID 5 for many years. That's not the same as LVM btw, which just abstracts the drive space for dynamic partitioning. The linux md daemon actually does the same thing that hardware RAID controllers do but lets your CPU do the heavy lifting of moving the data around instead of a dedicated processor on the controller cards.

    I'm pretty sure the Xserve machines don't have a hardware raid controller built into them. I think they want you to buy a RAID box for that. Sneaky Apple. I wish I had the dough.
     
  12. mrgreen4242 macrumors 601

    mrgreen4242

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    #12
    Bumping this old thread to see if there's any way to do RAID5 in software yet? If not, any talk of this for 10.6?
     
  13. blodwyn macrumors 65816

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    #13
    Why don't you try a RAIDZ array using ZFS?
     
  14. nownot macrumors regular

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  15. belvdr macrumors 601

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    #15
  16. buffyg macrumors newbie

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    #16
    Somewhat better yet: ZFS with raidz

    Better than using RAID 5 in many respects would be to use RAID-Z under ZFS, accepting the caveat that ZFS for Mac OS X remains a skunkworks project. RAID-Z can provide you with redundant distributed parity (raidz2), allowing you to accept higher levels of drive failure if you have larger numbers of drives.
     

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