topic BACKUP and continuation tapes in Operating System - OpenVMS

BACKUP and continuation tapes

Karl Rohwedder — Wed, 19 Jan 2005 04:16:55 GMT

We are using our backup procedures for years and I now notice a change of behaviour (or my memory has gone totally corrupt).
Scenario:
The backup command looks like:
$ BACKUP DISK:[...] Tape1:saveset,Tape2: ...
Backup starts on TAPE1 and continues the saveset on TAPE2. If it still needs more space it used to ask for another tape in TAPE2.
But on one system it requests the next tape on TAPE1, thus breaking the robot control procedures.
Has this been documented or may it be a bug?

(Its VMS V7.3-2 with all ECOs installed).

Re: BACKUP and continuation tapes

Ian Miller. — Wed, 19 Jan 2005 04:51:46 GMT

can you relate when the change happens to when you installed patches?

Re: BACKUP and continuation tapes

Bojan Nemec — Wed, 19 Jan 2005 04:58:19 GMT

Karl,

Are you sure that the contents of the backup fits to two tapes? The sequence can be like this:

start backup on TAPE1
continue on TAPE2
continue on TAPE1

Bojan

Re: BACKUP and continuation tapes

Mobeen_1 — Wed, 19 Jan 2005 05:19:06 GMT

Karl,
I am sorry could you please elaborate this?

rgds
Mobeen

Re: BACKUP and continuation tapes

Karl Rohwedder — Wed, 19 Jan 2005 06:02:40 GMT

I've checked some older logfiles and think I can understand now whats happening:

- Backup starts on tape1 with backup of disk1
- does disk2...
- finally tape1 is full and backups continues
on tape2
- now comes the backup routine into play:
- it checks for the device change and starts
the next backups on tape2, so it looks to
the user, that all continuation tapes are
to be loaded into tape2

The big change came, when some big disks were installed, which were bigger than 2 tapes.
Now backups for 1 disk start on tape1, continue on tape2 and request another tape. The backup procedure checks for continuation tapes and erreanously assumes, that the next disks had to be backupped onto tape2.

I hope my english is good enough to make the point clear.
So nothing is wrong with backup, sorry for the inconvenience.

Re: BACKUP and continuation tapes

Karl Rohwedder — Wed, 19 Jan 2005 06:04:36 GMT

Thread closed.