How shall I swap out a failing drive in a RAID array?

Victor June 22, 2011

The article at // doesn’t really address my issue. I have a RAID 0 array (I know, not the best setup, but that’s how my laptop came), where channel 4 is starting to fail. I bought a replacement drive, but now I’m unsure of how to swap out the failing drive.

  1. Brillig
    June 23, 2011 at 10:28 pm

    OK. I see I should have given more information. My hardware is a Vaio VGN-AW290 running Windows Vista 64 bit. I have a 3 disc recovery disc set that Windows created. I also have the drive backed up to an external hard drive and online using crashplan.

    So anyway, I don't know if this is a hardware or software RAID, but maybe the information I just provided helps to figure that out.

    I'm not really biased toward one way or the other to resolve this issue, and it's usually about a month between errors, so I've been procrastinating about it. And it's possible for the problem to be with the controller and not the drive, right? In which case, going through the effort of replacing a drive wouldn't be productive.

    So after this additional information, what would you recommend? I definitely have space on an external HD to store all of C: if needed. I'd be limited to USB 2 speeds.

  2. Mike
    June 23, 2011 at 8:54 am

    You cannot really exchange a Hard Drive in a Raid 0

    You need to (should) backup the data to a third storage, delete the Stripe, exchange the failing Hard Drive, initialize a new Raid 0 and then copy/clone back all the contents.The problem with Raid 0 is if one Hard Drive failed, is replaced or doesn't match up the entire Array is marked as failed. You could try to make a Sector-by-Sector clone from the failing Disk 2 to a new disk but if your controller ever checks the Serial, Model number or any unique identification the Array will be destroyed.Also since your drive is failing there is a chance that you will have a RW or IO error during the clone which again will render everything useless.
    Either way you will want to make a backup ~ especially before you attempt a SbS clone ~ at which point you can figure out yourself, whether you take the 50/50 chance with a clone or the working one via re-initializing and copying back the entire contents.

    • Smayonak
      June 23, 2011 at 2:48 pm

      Believe it or not, simply using the W7 system image tool has worked many times for me. I've gone from RAID 0 to RAID 1 and SSD to platter and back.  I have yet to experience a single issue using this method.

      It may be that the ICH10R chipset is more robust for creating and recognizing arrays. I'm not sure why, either, because hardware controlled (which is supposed to be superior to chipset) RAID 5 has been a dismal affair for me.

      • Mike
        June 25, 2011 at 12:43 pm

        If you have a Hardware Raid via ICH or a controller the Operating System (Win, Linux, Mac) sees the Raid as one Hard Disk, hence the Data will be imaged in whole ~ no matter which tool you use. With this backup/clone you can proceed whichever way you want (as you described)

        If you are running a Software Raid or put one of the Raid-Disks in some external HDD Adapter you will be able to access the Stripe individually (although access is kinda misleading, it will be an unknown/unrecognized Volume with a lot of garbage). If you want to clone only that single Stripe you do need a Sector-By-Sector clone.

        Looking at 500GB Raid 0 (2x250GB) full of data there will be a significant difference. 
        In the first case you will always backup/clone 500GB of Data.
        In the second case you would be able to clone only 250GB (one of the Disks) and replace it. But as mentioned before cloning a single Stripe is not the safest option. It can and should work but there is no guarantee.

  3. Smayonak
    June 23, 2011 at 7:23 am

    RAID 0 can be hard to backup, thanks to it splitting your data up over two hard drives, rather than one.

    I've used multiple methods of backing up RAID 0 drives and some methods have worked for me and others have not. Of the two methods I've used most (Clonezilla and Windows 7's disk imaging utility) the most effective has been Windows 7. That's because ICH10R treats two RAIDed drives as a single hard drive; it's just easier creating a system image, replacing the damaged drive and then copying the image onto the RAID array.
    From my experiences, swapping out a failing drive is a snap. In Windows 7 you simply go to "backup and restore" and choose "create a system image" from the left pane. Now you'll need a large external drive capable of holding the complete system image (sorry about that, but it is easier this way). Remember to also make a bootable "System Repair Disc" from this same pane. Once you have both the system repair disc and the system image, install the new drive (which should have already been initialized) and boot using the system repair disk. Then go through the restore from image process.
    If Windows 7 isn't your style, Clonezilla []supposedly includes RAID support and you can simply clone the damaged drive. However, this method has never worked for me, for whatever reason. I've used it in other applications and it's amazing. But so far, it just hasn't proven itself for RAID 0.By the way, I'm also assuming you are using a mobile version of the ICH10R Southbridge, rather than a software RAID 0 (the motherboard component controlling your hard drives). If you have a software RAID, this may not work. The reason is that a chipset RAID is handled at the BIOS level, whereas software RAID is handled by the operating system and is notoriously difficult to work with, particularly when dealing with recoveries.

    • Smayonak
      June 23, 2011 at 3:06 pm

      Mike pointed out a step I left out: you need to break up the array in your preboot RAID configuration menu. If it doesn't show up as an option upon boot, this menu is sometimes accessible in your BIOS menu.

      By the way, you wouldn't happen to have the Asus G73, would you?

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