Is Disk Utility "shrinking partition" for a week doing a defrag?

Question

And can I ever stop it, or will partition self destruct?
Summary:
2TB Partition, containing 1600-1700 GB (maybe 350GB free)
Attempted to Resize partion to 1.99TB (reducing size only 10GB) using DU GUI
Assumed it would take just a little while to move [up to] 10GB data into free space.
That was a week ago!  External 2TB drive on USB2, activity light flashing big time, random, misc short pauses (no patterns so looks like it's really working) 24/7 ever since.  Disk Utility says "Shrinking volume" with status bar about 60% complete and not moving since soon after beginning the process.
This archive wasn't backed up (stupid, I know).  So I bought another drive to do that with, but wanted to do a block copy to save time and to do that the program needed the source volume to be a tiny bit smaller in order to fit my destination.  (Stupid again, for the attempt before it was backed up.  I should have just done a simple copy!)  Yes, I've been kicking myself for a week now.
Some programs that do nondestructive volume or "filesystem" shrinking will do a complete defrag in the the process I believe.  Is that what's happening here?  Anybody know for sure? Can it really take this long with maybe 340GB free to work with?  I can't think of anything besides defraging that could explain this behavior.  Seems unlikely but could indexing be kicking in?  How many more days/weeks/months might I have to wait?  I really need this to be over.
If I stopped it, I wouldn't mind losing any one file (or a few), I just don't want to risk losing it all.  The Drive is an archive of mostly media files.  Many large files exist from 1.5GB to maybe 5GB, with few up to maybe 18 GB.  Lots of small files too.  All are rarely accessed and never edited (re-written) so I would guess there's not much cause for fragmentation.
Now to make matters worse, I use this computer for other things, and 3 days into the shrink, most of the computer froze.  Mouse moves but nothing is clickable. Clock stopped updating.  Can't bring up Force Quit.  At day 5 I tried again and noticed the dock would appear and magnify, until it froze too.  Drive still seems to be working with activity so I presume the shrink process is still alive.  I don't know if it will survive to completion however. How bad would things be if I just powered it off?????  Any other solution besides just wait for an unknown length of time?
Thank you for any help, and for not kicking me again while I'm down.
Mac Mini (Late 2009) 2.24Ghz, 4GB, 10.6.5

Answer 1

UPDATE: After more than three weeks of continuous disk activity, power to the external drive was accidentally turned off.  After rebooting the Mac and connecting the drive, all data seemed to be there, and was readable, and the drive was writable.  I attempted to back up the whole drive at once with a Finder copy (no OS on this drive) but it failed partway through.  A group of files copied with zero data, which I presume happened at the failure point with an incomplete write operation.  A piecemeal copy worked however, and all data was backed up intact I believe.  My guess is that some corrupted file caused all the problems (never located though), but it could have been a hard drive issue too.  If I learn more I'll do one more update.  But the point is, that simply stopping this failed shrinking process midstream did NOT destroy the partition or volume info, FWIW, although everywhere I looked on the web this prospect appeared very gloomy.  Bottom line, shrinking a partition of data without a backup is still a very risky prospect, and I will certainly never attempt it again.  I consider myself extremely fortunate that I did not lose it all, or even any!  OTOH, stopping a shrink is not guaranteed to have the dire consequences that one would suspect.  More testing would be necessary.