topic Re: Regarding Tape backup in Operating System - OpenVMS

Regarding Tape backup

Dipali — Tue, 04 Apr 2006 07:38:35 GMT

Hi

I am facing problem in back-up.for Data size to be backed up Max 1.8 GB,we need two tapes.I am using Tape drive TLZ07 &
tape used is DDS 4 20 GB .Operating system version is openvms 7.1. I do not understand why it required another tape as data to be backed up is less than tape size?

Dipali.

Re: Regarding Tape backup

Karl Rohwedder — Tue, 04 Apr 2006 07:46:55 GMT

The TLZ07 is quite old, I think it only handles DDS und DDS2 Tapes.

Be sure to specify the correct qualifiers with the INIT and BACKUP commands (/DENSITY=DDSx and /MEDIA=COMPACTION).

And keep in mind, that the compression facor depends on the kind of data, storing ZIP archives will not gain much from the tape's compression.

Also media errors and the size of redundancy blocks (/GROUP) may add a little overhead.

regards Kalle

Re: Regarding Tape backup

Karl Rohwedder — Tue, 04 Apr 2006 07:49:54 GMT

Just checked the Quickspecs, a TLZ07 may handle 4 GB uncompressed / 8GB compressed on a 120 m DDS-2 tape, so specify /DENS=DDS2/MEDIA=COMP at your commands.

regards Kalle

Re: Regarding Tape backup

Volker Halle — Tue, 04 Apr 2006 07:56:07 GMT

Dipali,

welcome to the OpenVMS ITRC forum.

Did you specify /REWIND to make sure, that the tape is being written from the beginning of the tape ?

Volker.

Re: Regarding Tape backup

Dipali — Tue, 04 Apr 2006 08:12:12 GMT

hi

thanks for your prompt reply.

is it ok that i am using DDs4/DDS10 tapes and use DENS=DDS2/MEDIA=COMP in command .is it work? or i have to define tape which i am using.

and what will be data integrity in that case?

Dipali