bzip2 issues

NiallC · 08-24-2003, 01:09 AM

(using suse 8.1)

I'm using the following command :

bzip2 filename

With a 48 Meg file, it reduced the file to 21M.

With a 22 Gig file, it compressed it to 18 Gig

These are hardly impressive numbers. The files I'm compressing are dd images of partitions from a hard drive.

What kind of compression should I be getting? and what can i do to achieve it?

TIA

Niall.

leonscape · 08-24-2003, 01:12 AM

Try using -9 as an option

bzip2 -9 filename

It increase the blocksize and should give you better compression.

NiallC · 08-24-2003, 10:37 AM

Thanks, I tried that on the 48M file, and it still came back as 21 M.

-9 is the default behaviour, I believe.

I'm stumped at this end.

I've seen other files compressed at at least 6:1 compression. If I could get my 21 Gig file to 4 gigs, I'd be leapin' for joy.

Niall.

mhearn · 08-24-2003, 10:56 AM

It depends a lot on what data you are compressing. Those ratios seem about right, to be honest.