IDS Forum

Re: Ontape backup

Posted By: Art Kagel
Date: Monday, 22 March 2010, at 1:08 p.m.

In Response To: Ontape backup (DEEPAK JOSHI)

Hmm, did you mean 7.31 or 7.13? Don't specifically remember a 7.13, but
versions prior to 7.30 also had problems during high update load with slow
archives. Also, early 7.xx releases (IB prior to 7.31xD8) experienced the
very old page bug which caused archives to run very slowly if the page
timestamps wrapped around past 2^31 (or more precisely wrapped so that there
were existing pages that have not been modified since the timestamp was last
set the such a low number. In this case the engine would have to update
every old page on disk that had a timestamp lower than the current wrapped
value when it was encountered during the archive. Once it started the
updates would go on for many months of archives before there were no longer
any pages with a timestamp old enough to cause a problem. It would then
reemerge several months later when the timestamps caught up to the next
oldest batch of pages.

Later releases fixed this performing the timestamp updates separately from
the archives.

Art

Art S. Kagel
Advanced DataTools (www.advancedatatools.com)
IIUG Board of Directors (art@iiug.org)

See you at the 2010 IIUG Informix Conference
April 25-28, 2010
Overland Park (Kansas City), KS
www.iiug.org/conf

Disclaimer: Please keep in mind that my own opinions are my own opinions and
do not reflect on my employer, Advanced DataTools, the IIUG, nor any other
organization with which I am associated either explicitly, implicitly, or by
inference. Neither do those opinions reflect those of other individuals
affiliated with any entity with which I am affiliated nor those of the
entities themselves.

On Mon, Mar 22, 2010 at 12:58 PM, Art Kagel <art.kagel@gmail.com> wrote:

> Backup times will depend on the IO throughput of the subsystem to which it
> is being written and of that of the chunks that are being backed up. Also
> if the chunks are on some of the same physical structures that the archive
> is being written to, there will be contention for the disk heads. Finally
> the configuration of the EMC RAID group that you are writing the archive
> file to will affect the back up throughput (ie RAID5 is 40% slower than
> RAID10 for sustained sequential writes which is what the archive is doing).
>
> Differences in archive times day to day can be due to activity on the
> server - more updates/inserts/deletes will require that more pre-image data
> from the physical log be copied out to the archive after each dbspace's back
> up is completed to maintain consistency of the archive. Another cause can
> be contention with other applications for IO bandwidth to the EMC array or
> even between the machine that is hosting the IDS instance and other machines
> on the network that may be sharing the same EMC array.
>
> Art
>
> Art S. Kagel
> Advanced DataTools (www.advancedatatools.com)
> IIUG Board of Directors (art@iiug.org)
>
> See you at the 2010 IIUG Informix Conference
> April 25-28, 2010
> Overland Park (Kansas City), KS
> www.iiug.org/conf
>
> Disclaimer: Please keep in mind that my own opinions are my own opinions
> and do not reflect on my employer, Advanced DataTools, the IIUG, nor any
> other organization with which I am associated either explicitly, implicitly,
> or by inference. Neither do those opinions reflect those of other
> individuals affiliated with any entity with which I am affiliated nor those
> of the entities themselves.
>
>
>
> On Mon, Mar 22, 2010 at 12:50 PM, DEEPAK JOSHI <djoshih@hotmail.com>wrote:
>
>> Hi All,
>>
>> We are running informix 7.13 on HP-UNIX 10.01. We are taking a weekly
>> level 0
>> backup of informix and writing backup to EMC clarrion. We noticed every
>> time
>> backup will complete at different time, usually it took 14 to 15 hrs to
>> complete. We have a database of size 36 GB.
>>
>> Is that the normal behavior of ontape to backup 36Gb of data in 14 to
>> 15hrs or
>> we can do something to complete it faster? Secondly, can anybody help me
>> to
>> troubleshoot why the backup time varies every time.
>>
>> Regards
>> Deepak
>>
>>
>>
>> *******************************************************************************
>> Forum Note: Use "Reply" to post a response in the discussion forum.
>>
>>
>

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Messages In This Thread

• Ontape backup
  DEEPAK JOSHI -- Monday, 22 March 2010, at 12:49 p.m.
  • Re: Ontape backup
    Art Kagel -- Monday, 22 March 2010, at 12:58 p.m.
  • Re: Ontape backup
    Eric Rowell -- Monday, 22 March 2010, at 1:04 p.m.
  • Re: Ontape backup
    Art Kagel -- Monday, 22 March 2010, at 1:08 p.m.
  • Re: Ontape backup
    Marco Greco -- Monday, 22 March 2010, at 2:15 p.m.

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