HP Sure Store DAT40 - compression

[Christian Dimov]

hey,

i'm new in this area.
i want to backup a server (SUSE 6.2) with tar-script on cronjob (to Sure Store DAT40).
How can i activate the compression (1/2). can i do that with tar or what i have to do?

Plz help me out

[Stuart Browne]

As far as I'm aware, the Compression on the DAT40 tape drives is configured to be Always-On Hardware cmopression.

You can't turn it off. It's always on.

If you are not getting enough compression of data->tape, and are using 'tar' to do your backup, then I suggest at the very LEAST throwing tar the '-z' switch (use libz compression (gzip)).

But if you can, use the '-j' switch (use libbz compression (bzip)).

I'd use libbz as a preference as it has higher compression rates.

If you do this however, the data you're throwing to the tape is already compressed, so don't expect to get much more than 20-25Gb to a DAT40i tape.

NOTE: You can't use both -j and -z at the same time.