other than performance, any dark sides to windows 2000 NTFS compression?

[Jeff]

I'm going to use a pair of 200 GB sata drives for backup & restore purposes.

If performance isn't a concern, are there any dark sides to enabling NTFS compression for the drives (in terms of data recovery if the worst happened, increased risk of corruption, etc?) Or is NTFS "compress this drive to save disk space" perfectly safe under windows 2000?

[Matt]

Hi Jeff,

I don't have direct experience with NTFS compression, but I would guess that it is not going to be as well supported by data recovery software-- particularly Linux-based recovery software. You might take another approach to your question, namely "does data recovery package XYZ support NTFS compression?" If you are connecting this pair as a RAID 1 configuration, you should be pretty safe respective to a disaster. The only question would be whether Windows ever corrupts compressed data. While I'm sure the compression is safe, the caveat is that if a bit of data DOES become corrupted, it is more likely to make that compressed file completely unreadable.

This is, of course, theoretical. I now defer to those with hands-on experience.
-Matt

[Kevin]

Jeff,
You should also consider if compression will actually help or not. Most modern data file formats are already compressed and the ones that aren't are usually only used for little files anyways. On most systems the only things that will get any compression at all are the applications themselves but not the data that they use. You should try compressing some typical data files and see if it does any good. If not then there isn't much point in worrying about data compression.

I have been using my old tape backup drive lately for archiving some large chunks of data (mpeg4 video) but the data is already so compressed that I can fit more onto the tape by turning OFF the hardware compression in the drive. This is what I have seen in my real world example:
DDS3 advertised capacity (with a * about compression): 24GB
Ammount of mpeg4 video I can fit on a compressed tape: 10GB
Ammount of mpeg4 video I can fit on an uncompressed tape: 12GB

I don't know what you plan to fill up those 200GB drives with but compression may be a waste of CPU cycles and it might even be a waste of disk space.

--
Kevin
-Backing up to uncompressed hard drives for several years now

[Randall]

On most systems the only things that will get any compression at all are the applications themselves but not the data that they use. You should try compressing some typical data files and see if it does any good. If not then there isn't much point in worrying about data compression. Our accounting data does compress rather well -- we get about 3:1 compression for our documents overall, which includes a lot of precompressed stuff, so some of the files must do a lot better than that. (I actually turned file compression off in one of our apps because it was taking so long for the files to decompress when we were ready to use them.)

I experimented a little with the NTFS compression at one point, but I don't think I'm using it anywhere now. I get the sense that it's safe enough, but I still remember all of those DoubleSpace horror stories and how every hard drive utility had warnings about compressed drives (and probably still do).

I'd be more inclined to trust per-folder compression than applying it to an entire drive. Some space-hogging files are less critical -- or let's just say that I can back them up uncompressed but would like to save some space with the "live" copy.

Randall