guess time, size of image for 4 Partimage compression levels

[powah]

How can I estimate the time & size of each image file for different compression level of the Partimage program before the image of the hard disk is generated?
i.e. What is the time & size of image file required for no, gzip, bzip2 & lzo compression?
I want to use this information to decide which compression to create an image file of less than 600MB for a 60GB hard disk which has about 40GB data (67% full).

[simon_irl]

you could just start partimage on each of these tasks and read the estimated time remaining from the screen (cancelling a partimage backup doesn't do any harm) but the estimates could be wildly inaccurate anyway. as well as the time varying greatly with hardware speed, effectiveness of compression varies greatly depending on the data you're compressing. if most of your data is already compressed (e.g. mp3's, jpeg's, etc.) then you may be very lucky to pack your 40GB drive down to 20GB...let alone 600MB!!! you're hoping for an image file that contains more than sixty times its size in data...there is no way in hell i'd get that with my data, but perhaps you have a lot of text or uncompressed media files? anyway, given the way compression varies with data, i don't think it's possible to give a generic estimate: your best option might be to examine the disk you want to backup to see what kind of data it contains, and then create a small test backup with similar data (so if it's 50% mp3's and the rest is mostly word processor documents, create a little test backup of maybe 100MB with 50MB of mp3's and 50MB of documents) and then run the test data through the various compression tools (gzip, bzip etc.) you're thinking of using.

based on how effectively they compress your data and how long they take, you'll have a benchmark from which you can estimate how long partimage would take to apply those same compression algorithms to your entire disk.