IDS Forum

Re: Log restore failing

Posted By: Martin Fuerderer
Date: Monday, 20 November 2006, at 8:33 a.m.

In Response To: Log restore failing (S SURESH)

Hi,

not sure which version of 7.31 you have. 7.31 is around
since a long time with many interim releases (aka fixpacks).

When you do log backup, you have to make a note of which logs
are on which tape (or in which file). This is why ontape writes out
this information. It can happen that a log file is backed up partially,
but ontape will tell that also in its output.

When you restore, you have to supply the tapes (or files) accordingly.
When ontape requests that the restore should begin with log file x,
then you have to provide the tape (or file) that contains log x.
It is your responsibility to know, which tape (or file) this is.
ontape is not concerned with whatever time you backed up log files.

When you start the level-0 archive at 8PM then it can be necessary
that for log restore you need to start with the log backup tape that you
(also) backed up at 8pm (rather than 8:12pm). Usually a running log
backup ("ontape -a") will immediately backup additional logical logs
if they become full while "ontape -a" is still running.
Say at 8pm when you start a log backup, the current log is 427 and
logs 423 - 426 have not been backed up (but are full). Now the log
backup starts working. While it is still backing up log 426, log 427
becomes full. The running "ontape -a" will also backup this log 427
on the same tape (as long as there is enough space).

With the above scenario, and with level-0 archive started at 8pm
as well, the restore will request to start with log 427. Thus you will
need as first tape the log tape of log backup at 8pm, not the log tape
from 8:12pm. That will be the second tape (containing log 428 and
up).

I assume that all your log backups were done correctly (i.e. no cases
of tape too small and backup somehow interrupted). In that case you
may have partial/incomplete log files on tapes. Things should still work,
but it gets more confusing which log file is on which tape.

Not sure if this explains your problem, but it is all that I currently can
say given your problem description.

Regards,
Martin
--
Martin Fuerderer
IBM Informix Development Munich, Germany
Information Management

Informix URLs list: http://home.arcor.de/mfu1/informix/urls.html

ids-bounces@iiug.org wrote on 20.11.2006 10:05:47:
>
> Hi all
>
> Im getting the following pblm on IDS7.31 on HP-UX box.
> I have 0 level backup(taken at 8PM) and im taking log backup every 12
mins,
> both
> using ontape.
>
> And i tried to restore(at 11AM nextday) 0level backup in another box i
> restored but when i tried to restore logs after that its giving error
>
> I have the logs after 8PM but when i tried to restore 8:12 PM log its
saying
> log no 874 required
>
> when i tried to restore 8:24 PM log its saying this log contains log
875.
>
> after every 12 mins i make a log switch and take bacup of the log
>
> Pls help.
>
> Suresh
>
>
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Messages In This Thread

• Log restore failing
  S SURESH -- Monday, 20 November 2006, at 4:05 a.m.
  • Re: Log restore failing
    H.G -- Monday, 20 November 2006, at 4:26 a.m.
  • Re: Log restore failing
    Martin Fuerderer -- Monday, 20 November 2006, at 8:33 a.m.

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