Need advice on dual Apple 512Gb SSD Raid setup

Discussion in 'Mac Pro' started by spacedesign911, Aug 25, 2012.

  1. spacedesign911 macrumors regular

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    Jul 22, 2010
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    Dublin, Ireland
    #1
    Hi guys, thanks for reading.

    I bought a mid 2012 hex core with Apples 512gb SSD & a 2 TB regular HD. I boot form the SSD and keep data on the HD, moving between SSD and HD is not ideal as its copies and not moves. So...

    I have a Macbook pro with Apples 512gb SSD in it, I dont use more than 60GB of the 512GB so I have replaced the 512Gb SSD with a second hand Apple 256GB SSD.

    No I have 2 Apple 512 GB SSD's for my Mac Pro, thing is one is a Samsung, one is a Toshiba. Can I Raid the 2 of these together to give me a 1TB SSD drive, with both booth and data on it?

    To clarify Im RAIDing a Toshiba and Samsung 512GB SSD, is this ok or bad?
     
  2. ColdCase, Aug 25, 2012
    Last edited: Aug 25, 2012

    ColdCase macrumors 68030

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    #2
    You will be fine. There are some RAID #s that need identical sizes, which you have anyway. I've RAIDed three or four different makes of SSDs before.

    Oh, it will be faster than rotational, but SSDs in a RAID may not be as fast as you may think.

    Many think you should partition the drive, one partition for your boot and OS, the other for your data. Gives yo less of a chance of data corruption, but I dunno if that matters much anymore.
     
  3. spacedesign911 thread starter macrumors regular

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    #3
    Thanks for the reply, appreciate it, my local Mac technician suggested no speed increase, thats ok with me, my goal is to get more capacity, so 1 TB of SDD is my goal. He suggested I set it up a s congelaticure of something sounding like this? as this will be more fail safe if one drive fails?
     
  4. ColdCase macrumors 68030

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    #4
    Concatenated, perhaps. You can typically recover data on one drive after you replace the one that fails. If you "stripe" them for performance, you would loose all the data. There are other RAID #s that give you more data protection at the expense of capacity.
     
  5. spacedesign911 thread starter macrumors regular

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    Jul 22, 2010
    Location:
    Dublin, Ireland
    #5
    Hi Coldcase, thanks for the reply, assuming your raid both 512gb ssd's and have 1tb of ssd space, how can you recover data if one drive fails, will the combined 2 ssds raided need to cap at 212gb storage?

    Anyone care to chime in with mixing both Toshiba and Samsung SSD drives being raided together?
     
  6. simplymuzik3 macrumors 6502a

    Joined:
    Jan 29, 2009
    #6
    If you want to have 1TB of SSD storage, then you'd need to use RAID 0. This does *not* provide any protection if 1 drive fails. RAID 0 gets you more space and more speed, but no redundancy at all.

    Use RAID 1 if you'd like to get failure protection. RAID 1 won't give you any extra space (so you'll still have 512GB), but if one drive fails, it'll be ok.

    It sounds like you want something to give you 1TB of space AND have redundancy. I'd recommend that you do RAID 0 with your 2 drives (giving you the space you want), and then buy another 1TB hard drive and use it for daily clones. I use SuperDuper which allows you to schedule daily drive clones. So each day your whole dual SSD RAID would get cloned onto the hard drive. If a drive ever died, you could just boot from your cloned drive and carry on. The most you'll ever lose is 1 days worth of data. Get another drive and use Time Machine with it if you want to make sure you have hourly backups (still do the daily clones though!).

    Someone please correct me if I'm wrong about the RAID portion. I know lots of you guys have much more RAID experience than me.
     
  7. ColdCase, Aug 27, 2012
    Last edited: Aug 27, 2012

    ColdCase macrumors 68030

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    #7
    Here's an old article with some simple explanations:

    http://reviews.cnet.com/8301-13727_7-10330301-263.html

    and:

    http://macs.about.com/od/glossaryil/g/jbod.htm

    What the tech recommended is the so called Concatenated Disk Set (JBOD), which is not normally considered a RAID, although the OSX disk utility can configure disks as a JBOD.

    I'm not an expert on recovery of JBOD, but many of the large capacity stand alone large drive enclosures are made up of several smaller drives. When I had one drive fail, the enclosure vendor replaced it and all the contents of the good drive was still there, files saved on the bad drive were gone. There are plenty of folks that use JBOD.

    If no one steps in here with JBOD recovery options, you may want to google JBOD and concatenated disks to get some background.

    I'm much more familiar with more traditional RAID sets.
     
  8. ColdCase, Aug 27, 2012
    Last edited: Aug 27, 2012

    ColdCase macrumors 68030

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    #8
    It doesn't matter if the drives are made by different manufacture. When you format them as a JBOD, the capacity numbers just add up. If you configure them as a RAID, when you format, the software will use the smallest size. So if one drive gives you 500GB and another 520GB, you will get a 1000GB capacity RAID0 (striped) or a 500GB capacity RAID1 (mirror).... or a 1020GB capacity JBOD.

    SSD vendors sometimes don't specify capacity the same, some include provisioning others don't. In the early days a 512GB class drive from one vendor may give you a useful formatted capacity of 450GB where another 500GB. I just mention it as that would be the only ramification of mixing drive vendors, that you may be surprised that the capacity the MacOS says you have is much lower than you expected.
     
  9. dia3olik macrumors member

    Joined:
    Sep 14, 2007
    #9
    if you use it for video editing you could try to swap one of the ssds with a unit from the same manufacturer to do a striped raid0 and have double the transfer rate...the hexa is not the bottleneck so feeding it with 500+ mb/s is much better than 250+ mb/s...the same for aperture and or lightroom, the raws will load faster...
     

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