veritas backup / compression

[billb]

how can i tell if my backup is being compressed - am using dlt's with veritas 10 but only getting bought 130gb on tapes n drive that should be 220 compressed. all the compressed options seem to be ticked any ideas?

thanks

[puggit]

You've been mis-sold the tapes (like everyone else). In reality you'll only get around 1.5x the native capacity (or .75 of the compressed).

It also depends what you are backing up - files such as .jpgs and .mp3s are already heavily compressed and you can't squeeze them much more. Files such as word documents have plenty of scope for compression.

Also try switching between hardware and software compression - might make a difference

[BliarOut]

And it's not a Netware volume you're backing up is it?

[billb]

no just general network shite - ie office files etc. so basically compression is bollox?

editted to say its on use hardware if not available software in veritas option - will there be any diff?

>> Edited by billb on Thursday 6th April 14:42

[puggit]

Could be a big difference

Other thing to do is update the firmware and drivers for the tape device

Also, if you could stop reminding me of my Veritas days that would be helpful

[billb]

puggit said:

Could be a big difference Other thing to do is update the firmware and drivers for the tape device Also, if you could stop reminding me of my Veritas days that would be helpful

updated firmware and drivers today so will see - veritas didnt like it when u used the dlt's own drivers so put them back to veritas's own. lovely software......

[lotusfan]

check the job specification, the default (IIRC) is compression hardware otherwise none
if your HW compression is off you can't then use software

[puggit]

billb said:

lovely software......

Try supporting it

[sjg]

It's just incredibly unlikely that your backup jobs will have much that can be compressed to half it's original size. As said, about 1.5x native is about right, and roughly what we get - mix of (S)DLT and LTO.

I always go on native tape capacity, and regard anything extra that you per tape from compression a bit of a bonus.

[billb]

lotusfan said:

check the job specification, the default (IIRC) is compression hardware otherwise none if your HW compression is off you can't then use software

is there an "on" button for hardware or should it be on if available by default? is def on in veritas

[puggit]

billb said:

lotusfan said: check the job specification, the default (IIRC) is compression hardware otherwise none if your HW compression is off you can't then use software is there an "on" button for hardware or should it be on if available by default? is def on in veritas

It's certainly not on by default. The best setting is what you had already - 'hardware if available, otherwise software'.