Re: ADSM Database reduction question
2000-02-01 11:22:40
Robert,
I can't remember where I found this info (list or manual) but here goes:
"The ADSM Server database has a b-tree organisation with internal references
to index nodes and siblings. The database grows sequentially from the
beginning to end, and pages that are deleted internally are re-used later
when new information is added. The only utility that can compress the
database so that "gaps" of deleted pages are not present is the database
dump/load utility. After extensive database deletion occurs, due to
expiration processing or filespace/volume delete processing, pages in the
"middle" of the space allocated for the database may become free, but pages
closer to the beginning or end of the database still allocated. To reduce
the size of your database sufficient free pages must exist at the end of the
linear database space that is allocated over your database volumes. A
database dump followed by a load will remove free pages from the beginning
of the database space to minimise free space fragmentation and may allow the
database size to be reduced."
We have exactly the same problem on our ADSM servers. As far as I
understand the only way round this is to perform a dsmserv dumpdb and
loaddb. I think it was mentioned on the list recently that an online defrag
tool would be useful.
Last weekend we tried this on our server (10gb database, 0.5gb memory, AIX
4.3, SP wide node). The dumpdb took just over an hour. We had to cancel
the loaddb as we were looking at a 72 hour load time. We restored the
database from a normal DB backup.
We still have the problem, so if you do find another way, please let me
know.
Richard.
=====================================
Technical Services (ADSM) - Dawson House
Int: 33298 Ext: 01925 233298
=====================================
> -----Original Message-----
> From: Burton, Robert [SMTP:ROBERT.BURTON AT ROYALBANK DOT COM]
> Sent: 01 February 2000 15:57
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: ADSM Database reduction question
>
> We have a 23,576 MB database, that originally was running at 94% utilised.
> By moving clients to other servers and
> deleting filespace we have reduced our capacity to 37.3%. We are trying
> to
> reclaim some database volumes.
> We have a spare 1112 MB of free space in the database. According to my
> calculation 37% of 23576 MB is approx.
> 9000 MB which means we have large quantity of wasted space in the
> database.
>
> Is there anyway to compress the database to get rid of the wasted free
> space? I tried deleting database volumes using our freespace in the
> database. This did not reclaim the space on the deleted volume it just
> copied the volume being deleted (valid data & space) to the freespace.
>
> Any suggestions would be appreciated....
>
>
> Robert Burton
> Open Systems Storage Analyst
> Royal Bank of Canada
> (416) 348-3849
> Robert.Burton AT RoyalBank DOT com
**********************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.
This footnote also confirms that this email message has been swept by
MIMEsweeper for the presence of computer viruses.
www.mimesweeper.com
**********************************************************************
|
|
|