IDS Forum

RE: Backup/Restore

Posted By: Martin Fuerderer
Date: Monday, 29 September 2003, at 3:43 a.m.

In Response To: RE: Backup/Restore (Paul Hartman)

Hi,

since it was the physical restore that took such a long time before,
I would rather think that ontape's reading from the tape device was
slow. Have you configured the TAPEDEV as a remote tape device
on the machine where you restore ? I.e. the tape device from the
production machine where you take the archive as a remote tape
device on the restore machine ?
I would suspect this to be the slow link in the chain ...

You could check for this by writing/reading from the tape device on the
2 machines via Unix system utility "dd" and measure the throughput.

If you're just taking the tape from the archive machine to the restore
machine (using local tape devices), then a different blocking factor of
the tape devices might still cause you problems. Some tape devices
even "decide" to rewind automatically as soon as the application
(here ontape) intermediately stops an ongoing read or write operation.
In that case continuing the reading will first require wind forward
to where it paused before. This can sometimes slow very fast tape
devices to a crawl ...

I do not think that a slow connection from ontape to the controlling
terminal
really is the problem, because after the physical restore has started
there are (as far as I know) no outputs from ontape to the terminal until
the physical restore is done ...

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





"Paul Hartman" <Heartware@freeler.nl>
Sent by: forum.subscriber@iiug.org
28.09.2003 20:54


To: ids@iiug.org
cc:
Subject: RE: Backup/Restore [1945]



Hello ,

This weekend we restored the database and there was a normal restore time.
I really don't know why. Maybe because a third party has made some
impriovement to the network.
Is it possible that a bad network connection,a bad connection from the
tty-terminal with the machine and e.g. a bad connection from ontape with
the terminal can cause performance problems? That day we had a network-dip
and we lost connection with the tty, and ontape too. In that situation
ended
ontape his actions , freed his memory and rew the tape.
Could it be that ontape every second watches if the connection exist?

Thanxs in advance,

Paul Hartman

-----Oorspronkelijk bericht-----
Van: forum.subscriber@iiug.org [mailto:forum.subscriber@iiug.org]Namens
Paul Hartman
Verzonden: dinsdag 23 september 2003 21:28
Aan: ids@iiug.org
Onderwerp: RE: Backup/Restore [1915]


Hello,
Let me answer all questions and give some future answers:
We're using ontape -r, with a blocksize of 128 Kb
The system is about 8 Gb
I'm NOT restoring any logical logs
The system is NOT busy. sar is about 95% idle.
And the time I'm talking about is just the time for restoring the chunks
from
tape.
The chunks aren't cooked. We use 29 raw chunks.
The log file just describes the start and the end of the restoration. Only
checkpoints are showed.
There can be open transactions. The snapshot (level 0 tape backup) occurs
in
bright daylight. The Physical and Logical Recovery takes about 10 minutes.
ACX (Access Control from CA) runs also on the machine as a kernel
extension.
But the party that rules that application(Security) doesn't see any
violations.

Maybe someone does ring a bell?

Thx in advance,

Paul Hartman


-----Oorspronkelijk bericht-----
Van: Martin Fuerderer [mailto:MARTINFU@de.ibm.com]
Verzonden: maandag 22 september 2003 11:57
Aan: Paul Hartman
CC: forum.subscriber@iiug.org; ids@iiug.org
Onderwerp: Re: Backup/Restore [1908]


Hi,

the information you're giving is quite general.
Can you be more specific ?

E.g. regarding following considerations:

- what backup/restore method are you using ?
(ON-Bar, ontape, onarchive ?)

- how big is the system that you're backing up ?
(onstat -d output helps counting used pages vs. free
pages ...)

- are you restoring logical logs also ?

- is the system very busy while the backup is taken ?
(re-playing many log records takes some time.)

- are there open transactions when the backup is
taken ? Are they rather long ?
(even when not re-playing logical logs, open transactions
need to be rolled back upon restore. If they were long
at backup time, rollback will take considerable time.)

- are you using cooked files on the restore-system ?
(if they have "size of zero" at restore time, they need to
be "blown up" to the necessary size. On some systems
this can be rather slow.)

- check your OnLine Message Log file of the restored
system. This will tell more specifically, which phase of
the restore takes long.
(If you're using ON-Bar, also check the ON-Bar Activity
Log file.)

I hope this gives you some ideas.

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





"Paul Hartman " <Heartware@freeler.nl>
Sent by: forum.subscriber@iiug.org
22.09.2003 09:03


To: ids@iiug.org
cc:
Subject: Backup/Restore [1908]



Hello,

We're running on AIX 4.3, ids 7.31. The backup of the system lasts for
about 30 minutes, but the restore(on a duplicate test-system) lasts 3
hours. I heard that the restore may last 2 or 3 times the backup time, but
3 hours is too long. Nobody could find anything in soft- or hardware. Does
anybody know this problem on aix-systems, is there a known problem? I'll
be delighted if someone can help us.

Thanks in advance,

Paul Hartman
Netherlands

Messages In This Thread

• Backup/Restore
  Paul Hartman -- Monday, 22 September 2003, at 3:03 a.m.
  • Re: Backup/Restore
    Martin Fuerderer -- Monday, 22 September 2003, at 6:00 a.m.
  • RE: Backup/Restore
    Priest, Darryl - BALTO -- Monday, 22 September 2003, at 9:18 a.m.
  • RE: Backup/Restore
    Paul Hartman -- Tuesday, 23 September 2003, at 3:27 p.m.
    • RE: Backup/Restore
      Paul Hartman -- Sunday, 28 September 2003, at 2:54 p.m.
      • RE: Backup/Restore
        Martin Fuerderer -- Monday, 29 September 2003, at 3:43 a.m.
    • Re: RE: Backup/Restore
      ESTEBAN RIEZNIK -- Tuesday, 30 September 2003, at 6:07 p.m.
      • RE: RE: Backup/Restore
        Mike Badar -- Tuesday, 30 September 2003, at 7:43 p.m.
      • Re: RE: Backup/Restore
        Martin Fuerderer -- Wednesday, 1 October 2003, at 3:14 a.m.
        • Re: RE: Backup/Restore
          John Bejarano -- Wednesday, 1 October 2003, at 1:40 p.m.
          • Re: Re: RE: Backup/Restore
            ESTEBAN RIEZNIK -- Tuesday, 7 October 2003, at 6:22 p.m.
      • RE: RE: Backup/Restore
        Konikoff, Rob (Contractor) -- Wednesday, 1 October 2003, at 10:45 a.m.
      • Re: Backup/Restore
        Jean Sagi -- Friday, 3 October 2003, at 7:16 a.m.
  • Re: Backup/Restore
    ESTEBAN RIEZNIK -- Wednesday, 1 October 2003, at 9:51 a.m.
  • Re: Backup/Restore
    ESTEBAN RIEZNIK -- Wednesday, 1 October 2003, at 11:41 a.m.

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