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4TB External Raid Array shows up as 2.2TB

1913 Views 6 Replies Latest reply: Sep 18, 2011 5:29 AM by pgf RSS
Neo911 Level 1 Level 1 (5 points)
Currently Being Moderated
Feb 28, 2011 1:11 PM
Hey, I bought a couple of Mercury Elite AL Pro FW800 hard drive enclosures from OWC. Picked up two Western Digital WD20EARS Caviar Green 2TB and two Seagate Barracuda LP 2TB SATA2 drives here. Each enclosure has a matching set of above drives. The enclosure allows for the following set ups:
1. Independent
2. JBOD
3. RAID 0

When using the hardware RAID 0 set up and formatting with Disk Utility in OSX to extended journaled, the drives only show up as 2.2TB not 4(approx). Anyone know why this is and how to get something closer to 4TB to show up? I can set the enclosure to "Independent" and use DU to create a software RAID array and that shows up as 4TB no problem. "Independent" itself shows 2 separate drives of 2TB each in each enclosure. I would like to utilize the hardware RAID aspect of the enclosure as I have 2 of these bad boys connected to a Mini that will be used for some video encoding. My understanding is that there is a performance and reliability gain with hardware RAID.

I'm running Mac OSX 10.6.6 and using a FW800 connection.
MacMini 2.4ghz 2gb ram 500GB, Mac OS X (10.6.6)
  • Kappy Level 10 Level 10 (221,015 points)
    Currently Being Moderated
    Feb 28, 2011 1:28 PM (in response to Neo911)
    Be sure you haven't set them up to be a mirrored RAID. I believe those enclosures provide for one or the other internally.
    Mac Pro 2.66 Ghz; MBP Unibody; MBP C2D 2.33 Ghz; 11" MBA, Mac OS X (10.6.5), iMac C2D 17"; MB 2.0 Ghz; iPad 32G; 80GB iPod Video; iPod Touch; iPod Nano 2GB
  • Kappy Level 10 Level 10 (221,015 points)
    Currently Being Moderated
    Feb 28, 2011 2:20 PM (in response to Neo911)
    So the setup is two 2 TB drives in a striped RAID in each enclosure? But you say Disk Utility only reports 2 TBs. Am I understanding correctly?

    How are each of the drives being formatted prior to putting them into the array?
    Mac Pro 2.66 Ghz; MBP Unibody; MBP C2D 2.33 Ghz; 11" MBA, Mac OS X (10.6.5), iMac C2D 17"; MB 2.0 Ghz; iPad 32G; 80GB iPod Video; iPod Touch; iPod Nano 2GB
  • The hatter Level 9 Level 9 (58,545 points)
    Currently Being Moderated
    Feb 28, 2011 2:28 PM (in response to Neo911)
    Some cases may have a toggle switch or jumper.

    What you should be doing is talking to OWC.

    Some cases don't support 3TB volumes and show up as 2.2TB.

    When I saw the thread title, I actually assumed it was OWC RAID5 w/ 4 drives.

    You aren't trying to add the two cases into a single array, for one thing, you don't want to daisy chain, and for another, even the WD Green 64MB cache are faster, faster than FW800 interface (though that should not affect total capacity).

    Some people use Disk Utility to create the RAID. In which case all 2 or 4 drives would have to be seen as 4 unique drives.

    Mixing two brands or models into one array is never a good idea. And not all Green drives work as RAID or at least not supported.

    http://www.macsales.com/firewire
    http://eshop.macsales.com/shop/hard-drives/RAID/Desktop/

    http://blog.macsales.com/6678-price-drops-on-the-qx2-makes-capacity-and-performa nce-even-more-affordable
    Mac Pro 8800GTX Corsair SSDs, Mac OS X (10.6.5), 3.2GHz 10K VelociRaptors Win7 GTX 460
  • pgf Calculating status...
    Currently Being Moderated
    Sep 18, 2011 5:29 AM (in response to Neo911)

    I had a similar problem.

    Maybe you can be interested:

    Re: Using a 3TB external drive?

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