IDS Forum

RE: Information on Log Backup

Posted By: Meza, Silvana
Date: Thursday, 27 May 2004, at 11:48 a.m.

In Response To: Re: Information on Log Backup (Martin Fuerderer )

What does the "ontape -p" do?

-----Original Message-----
From: Martin Fuer.... [mailto:MARTINFU@de.ibm.com]
Sent: Thursday, May 27, 2004 4:14 AM
To: ids@iiug.org
Subject: Re: Information on Log Backup [3036]


Hi,

when you do "ontape -r" it will do both, physical restore and after that
logical restore.
There's no need to do an extra "ontape -l". (That would only be necessary
if you would
have done "ontape -p".) "ontape -r" will ask for the respective tapes,
including the log
tapes.

After the physical restore (i.e. data chunks of your dbspaces), "ontape
-r" will ask for
the correct tape with logical logs. This will be a prompt roughly like:
"Logical log restore should begin with log number x ."
where the log number is the logical log unique ID. At this point you have
to provide the
correct log backup tape which contains this logical log. Any other (log
backup) tape
will be rejected.
This is the reason why during log bckup upon completing a log backup tape,
ontape
("ontape -c" or "ontape -a") will tell you which logical logs are
contained on that
specific tape. Making a note of this will save you searching and trying
log backup
tapes during restore (where usually there's little time because everybody,
your boss
included, impatiently waits for the restore to be completed ...).

This means that for a successful restore up to "now", you have to have all
logical log
backup tapes written (i.e. completed) between the backup time of the
(level 0) archive
that you have restored and "now". This may include a tape with salvaged
logical logs.

You are writing one logical log tape each day, if I understood you
correctly.
In that case after restoring yesterday's archive (physical restore), you
will then first
be asked for the logical log backup tape from yesterday. After restoring
the necessary
logs from that tape (ontape will choose the correct logs to restore by
itself), you can then
restore logs from today. You will be prompted somewhat like: "Do you have
another
logical log backup tape ? y/n", so that you can restore consecutive
logical logs from
as many log backup tapes as you want ... The keyword here is
*consecutive*. There can
not be a gap between logical logs, as this would make things inconsistent.

Regards,
Martin
--
Martin Fuerderer
IBM Informix Development Munich
Data Management Solutions

forum.subscriber@iiug.org wrote on 27.05.2004 06:29:42:

> Hi,
> I am using IDS 7.x on Windows NT server. I would like to know that if we

> take continuous log backup on informix with the following command
'ontape
> -c' on one tape during the day.
>
> Can you please advise that if we restored the previous days database
backup
> with "ontape -r" and then on top of that if we restored today's log's
backup
> "ontape -l", will it work and will I get the data as on now then.
>
> Thanks and Regards
> VAIDYANATHAN KRISHNAN
> (GANESH)

Messages In This Thread

• Information on Log Backup
  Vaidyanathan Krishnan -- Thursday, 27 May 2004, at 12:29 a.m.
  • Re: Information on Log Backup
    Martin Fuerderer -- Thursday, 27 May 2004, at 5:14 a.m.
    • Re: Information on Log Backup
      John_Caron@mab.uscourts.gov -- Thursday, 27 May 2004, at 8:07 a.m.
      • Re: Information on Log Backup
        Gerd Kaluzinski -- Thursday, 27 May 2004, at 9:49 a.m.
    • Re: Information on Log Backup
      Martin Fuerderer -- Thursday, 27 May 2004, at 9:14 a.m.
    • RE: Information on Log Backup
      Meza, Silvana -- Thursday, 27 May 2004, at 11:48 a.m.
      • RE: Information on Log Backup
        Terrence Mullins -- Thursday, 27 May 2004, at 12:38 p.m.
      • RE: Information on Log Backup
        Paresh Rathod -- Thursday, 27 May 2004, at 1:00 p.m.
      • RE: Information on Log Backup
        Darren_Jacobs@carmax.com -- Thursday, 27 May 2004, at 1:38 p.m.

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