pb backup DLT tape

[Bachelier]

I want to backup with a DLT tape, but there is a message in SAP unattended mode impossible, volume remount required, I think that the capacity (37G -75Gcompressed) is reached, I want to compressed data to make the backup. Can you help me.
Thanks, regards
Nicolas bachelier

[Ken Scharpell]

By default data compression is normmaly ON for DLT drives so you are writing it compressed. How much data are you actually trying to back up (total it up) and what model of DLT and Tapes are you using ? (These determine how much you can backup to 1 tape)

[Bachelier]

I have DLT7000 (35G-70G compressed) HP ov
omniback II LTU, I want to backup 37G

[Andreas Voss]

Hi,

if you using SAP integration with omniback you can activate software compression at 'SAP Backup Specification'.
When opening 'Backup Options' you get a window 'SAP options' that contains a toggle button 'compress'

Regards

[Ken Scharpell]

Are you using a compact IV tape ? which is rated up to 70GB ?

35GB is the amount of data that will fit on the tape if it cant be compressed. Under 'optimal' conditions at least some data can be compressed hence tape drive manufacturers conservatively rate compression at only 2:1 (35-70Gb). If you backup 100Gb of text files they will fit onto a single tape no problem as the compression ratio will be somewhere around 5:1+. If youre trying to backup 37Gb of binary files (images - movies, jpegs, binary databse files) then you probably wont get any compression at all which means around 35Gb is all you can fit onto a single tape. It depends on the data you are trying to backup.

what does lssf /dev/rmt/?m on your DLT drive device file show ? It should be something like;
stape card instance 4 SCSI target 3 SCSI LUN 0 at&t best density available at address 0/3/0/0.3.0 /dev/rmt/0m

which confirms compression should be on - unless someone changed the DIP swithes on the drive itself - you may need to check them.

[Carlos Fernandez Riera]

Latest versions of stm can show amount of data transfered and compression ratio. Select your DLT and run information