topic Re: tape backup problem in Operating System - HP-UX

tape backup problem

kholikt — Tue, 27 Feb 2001 06:43:47 GMT

We have a server that contains around 17GB of data. Currently, we are trying to backup the server using a DDS3 tape. However, the tape drive will backup up to 16GB only and it will actually required for second tape. We are using Omniback to start the backup.

The tape has been reinitialized to 24GB before use. My question here is what could be the possible cause that omniback required two tapes instead of one?

Is this possible that the tape drive is faulty. By the way, DDS3 theoriticaly should be able to handle around 24GB kind of capacity with compression on.

Any help will appreciated

Re: tape backup problem

Peter Finn_1 — Tue, 27 Feb 2001 09:35:17 GMT

compression, is of course, very much depending of what kind of data is compressed. DDS3 has a native capacity of 12GB and can be as much as 24GB if a 2:1 compression ratio can be achieved, which is not always the case

I believe that you can monitor in omniback the amount of data omniback is sending to the device in the monitor screen. (not sure about this)

Re: tape backup problem

Bruce Regittko_1 — Tue, 27 Feb 2001 15:33:40 GMT

Hi,

With DDS3, you get 12GB native, that is, with no compression. Under ideal conditions, i.e., large text files, you may approach 24GB or 2:1 compression.

The data you are backing up will limit the amount of compression.

You may consider obtaining a DDS4 drive.

--Bruce

Re: tape backup problem

Vincenzo Restuccia — Mon, 26 Mar 2001 15:47:49 GMT

If the data is compressed you have need of two tape.Verify it with fbackup.

Re: tape backup problem

Mark Vollmers — Mon, 26 Mar 2001 16:38:36 GMT

Can you dictate the compression ratio? If not, is it feasible to compress some or all files (with gzip or something) before backup (with cron) to get below the 16 GB level. Might save you from buying a new drive.

mark