Tuesday, January 15, 2008

PartitionMagic it isn't

In my previous post, I gave the story of how I went from a pair of 320GB RAID1 volumes to a single 750GB RAID1 volume. While that post wasn't very Vista-specific, it set the stage for this post: how I used the additional space.

Since I acquired my first iPod, I've been creating a separate, un-named NTFS volume, which I would then mount on the system (C:) partition; after doing that, I would use TweakUI (on XP) to point the "My Music" virtual folder to the mounted volume. With this technique, I have been able to constrain the space consumed by my iTunes library in line with the space available on my iPod. Having started with a 40GB "third gen" and later upgrading to the 60GB "iPod with Video", I've had to resize the volume, but it otherwise works very nicely.

And by having a separate volume, it's really easy to segregate the backup of the system versus data partitions.

When I rebuilt the RAID-0/1 into 2x RAID-1, I didn't "carve out" a 60GB chunk for the iTunes from the first RAID-1 set: as it was, I was having to deal with 2x 320GB virtual volumes, and carving the first one into 64GB for Vista, 60GB for music and the remainder for ?. I had the other 320GB for data, so I just gave up: the first 320 volume kept the 64GB Vista partition, and the remainder was mounted as my iTunes store. Lots of wasted space, but it kept the drive letters the same.

But with my reconfig, I'm back to a single volume to carve up as desired. I already had the 64GB Vista partition the way I wanted it, but now I had a 200+ GB NTFS volume where I really only wanted a 60GB. PartitionMagic was out; although I have a licensed copy, it only behaves on my system when run under NTLDR and the nVidia RAID driver is properly loaded.

So, I decided to play with the new Vista drive manager option for shrinking a volume.

Turns out, it works very well. Select a volume to shrink, right-click and select "shrink volume..." The dialog that follows will let you know the maximum space that can be recovered from the volume. Adjust to your desired amount, and click the "Shrink" button.

There are a some major limitations to the tool, however:
  • Disk Manager will only truncate space from the last bit of data to the end of the volume. You'll definitely want to run defrag to get as much data shoved to the front of the drive as possible before running.
  • Even if you have an empty volume, you may find you can't shrink the volume by more than half the empty space. That's because the normal place for the NTFS MFT is the "middle" of the volume. The only way to reclaim more space is to run a boot-time defragger that can re-optimize the location of the MFT: once you truncate all the space possible, the MFT is left at the end of the drive. The boot-time defrag will move the MFT to the "middle" of the new volume, creating another large slack space that can be used to shrink the volume. Personally, I use Raxco's PerfectDisk 8 Pro.
  • Disk Manager cannot move a partition to consolidate free space, so plan out your partition layout before you start shrinking and moving things around.
So I ended up using two passes to shrink the iTunes volume to 80GB (yes, I'm considering another upgrade), followed by creating a new NTFS volume to use the remainder of the space.

I copied some of the stuff I wanted on fast storage from the drobo, and now I'm sitting pretty with the new setup.

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