Mac Pro - do i need the raid card?

Discussion in 'Mac Pro' started by NRose8989, May 19, 2008.

  1. NRose8989 macrumors 6502a

    Joined:
    Feb 6, 2008
    #1
    I've read quite a bit of threads and articles about raid but i still can't find an exact answer for my problem. I'm planning on buying a mac pro soon so I'm pricing everything out but can't decide if i really need the apple raid card. I'm a student developer and plan to use a mac pro for development (possibly video and photo work as well) and also be a media server for my house. I plan to use raid 0 but im not sure if it would be best to just use mac os X software raid 0 or spend the extra $640 (apple.com developer discount) for the apple raid card. I'm not so worried about spending the extra money on the hardware for better performance but I'm more concerned about spend more money for hardware raid when i can get the same results using the software raid. thoughts?
     
  2. yellow Moderator emeritus

    yellow

    Joined:
    Oct 21, 2003
    Location:
    Portland, OR
    #2
    IMO, if you're just using it for RAID0 (or 1), then just do software RAID.
    That box has PLENTY of processing to devote to RAID.
    I think the card is only worth it if you need to do RAID5.
     
  3. Consultant macrumors G5

    Consultant

    Joined:
    Jun 27, 2007
    #3
    Sounds like you don't need it.

    Before doing Raid, you should actually read about the benefits and RISKS of Raid first.

    Mac Pro has enough power for what you do even without raid.
     
  4. NRose8989 thread starter macrumors 6502a

    Joined:
    Feb 6, 2008
    #4
    thats another thing that i was contemplating. would i really see a performance boost say if i did 2 x 500GB drives in raid 0 or just go with a 1 TB drive non-raid setup. also how is raid 0 more of a risk other than if one drive fails = all drives fail. does raid put extra stress on the drives that causes them to have a higher failure rate?
     
  5. DeuceDeuce macrumors 6502a

    DeuceDeuce

    Joined:
    Aug 8, 2007
    Location:
    San Dimas, CA
    #5

    What he said above.... Plus, is it stupid to use two different branded HD's to set up a raid 0 and have it be used as my Time Machine to back up my 640gb?
     
  6. StealthRider macrumors 65816

    StealthRider

    Joined:
    Jan 23, 2002
    Location:
    Yokosuka, Japan
    #6
    Using a RAID0 array as a backup solution is possibly one of the dumber things you could do - RAID0 has a pretty high risk of failure.
     
  7. kingtj macrumors 68020

    Joined:
    Oct 23, 2003
    Location:
    Brunswick, MD
    #7
    I'm not a "RAID expert", but ....

    I have worked with it a fair bit, doing systems administration for different companies I've worked for. Here's my take on it:

    RAID 0 is NOT going to make drives "wear out faster" than not using RAID. Technically, it should *slightly* reduce wear on any one drive, since the usage is more spread out between the pair of drives in the RAID 0 striped set.

    The problem is exactly what someone else stated. If one drive fails, you're going to suffer data loss across the whole RAID 0 set. (It's kind of like saying "If I roll this die and it comes up a 1, that's like a drive crash that loses all my data. If it comes up 2 through 6 though, we're good." Now, take two dice and do the same thing, except the rule is now modified to say "If either or both of these rolls a 1, we have a drive crash with data loss." You'd probably prefer taking the chance rolling only 1 die, instead of 2, wouldn't you? That's a non-RAID drive vs. a RAID 0 pair of drives.)

    The ONLY reason to do RAID 0 is strictly for performance. You don't need this performance boost for Time Machine backup purposes. (It happens in the background while you use the computer anyway, and Time Machine should be backing up to a drive that's not used by your applications for anything else. It shouldn't "bog down" the program loading and document saving you're doing as you work.)

    If you want more data *reliability*, you want to go with RAID 1 or 5. RAID 1 makes a mirror image of one drive on the second drive, so if one fails - you're just warned of the fact, and things continue as normal, using the drive that's still working. When you replace the bad drive, the system automatically re-images it with a copy of what's on the other drive again. RAID 1 is a LITTLE bit slower writing data than not doing RAID at all, because it always has to ensure BOTH drives contain identical data. But it's SLIGHTLY faster reading, because it will grab data from whichever drive has its drive heads closer to the sectors you're looking for at that moment in time.

    RAID 5 is nice when you have more than 2 drives and you're trying to get that type of "if a drive fails, just tell me, continue on, and rebuild data on the replacement when I feel like sliding it in" capability - BUT you don't just want a plain old mirror image of one drive kept on the second one. It's more complex in how it stores "checksum" data across the set of drives, and gives you 2/3rds. of your total drive capacity as usable space at a given time, vs. only 1/2 your total space like a RAID 1 mirror would do.


     
  8. DeuceDeuce macrumors 6502a

    DeuceDeuce

    Joined:
    Aug 8, 2007
    Location:
    San Dimas, CA
    #8
    Thanks for the clarification, so if I already have two 500gb hardrives laying around it would be a very bad idea to use them for Time Machine in RAID 0 rather then spending a couple hundred bucks on a 1TB drive.

    I understand that if one fails Im screwed but it would be for backups anyway so I would have to have 2 drives fail for me to be screwed anyway. The 640gb and one of the 500gb.
     

Share This Page