Upgrading a RAID1 array with Parted Magic

Over this past weekend, I was tasked with upgrading disk space on one of our servers, a Dell PowerEdge 860. It has SAS 5/iR, originally with 2 160GB SATA disks mirrored. The data partition was down to only a couple GB, so it was in bad need of an upgrade. A little over a year ago, I performed a similar upgrade on a Dell Precision 390 – that had 2 750GB disks mirrored which was upgraded to 1.5TB array. To conserve resources, I used the 750GB disks to upgrade the array on the PowerEdge, along with a copy of Parted Magic, an open-source partitioning tool.

In brief, here’s the steps I took to perform the upgrade:

  1. Perform a full backup and defragment the drive. This process could potentially hose all the data on the disks, so a backup is a must. This server is running Win 2k3, and NTFS partitions are happier being resized after being defragmented.
  2. Power down the server and remove the original disks – be sure to mark them, preferably taking note of the primary disk of the array.
  3. Install the new disks, boot into the controller bios and build the new array.
  4. Power down the machine again. Remove the secondary disk of the new array (mark it!) and install the primary disk of the old array on another channel. The PowerEdge had on-board SATA channels, so I hooked it up there.
  5. Boot into Parted Magic. I used a CD, but there are USB drive and PXE options.
  6. Start up G4L. Do a raw copy, and select your source and destination disks. The disks are listed in standard *nix nomenclature (e.g. /dev/sda) with the size in bytes. Start the clone process. This can take some time. In this case, it took about 1hr 15mins to clone the disk. When I did this earlier on the Precision workstation, it took about 12hrs.
  7. Shut down, remove the primary from the original array and restart, just to be sure everything works.
  8. Shut down again and reboot into Parted Magic. Run Gparted to resize the partition.
  9. Reboot. After resizing, Gparted marked the partition as dirty, so chkdsk will run to make sure nothing’s broken.
  10. If everything looks good, shut down one more time to install the secondary disk of the new array. Reboot and enjoy the added space.

After this process, the array will be degraded, and consequently the machine may be sluggish until the disks sync. Performing this upgrade on the PowerEdge 860 took about 3hrs from start to finish, which was much better than the 15hrs that it took for the Precision 390 a year ago. In the latter case, a 750GB disk was being cloned, with much of the time consumed with the cloning process. This process should work with just about any RAID1 configuration, though YMMV.

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