Change Tablespacedesign?

[janlars_goedtke]

Hello,

we want to convert an ECC 6.0 DB6 V8.2 System to Unicode.

This system has a size of 300 GB.

Should we change the DB layout during the export-import procedure (change from the old degign with 20 or more tablespaces to only 5 or 6)?

Does it make sense for big systems to use the reduced design (e.g. according to I/O behaviour)? Or is it better to use more tablespaces? The pagesize of the tablespaces will be changed by us.

Thanks

Jan

[Former Member · Accepted solution]

Hi!

I would say that it depends of your storage. We reduced the number of sapdatas from ~80 to 8 and increased the size of the container files during the Unicode conversion of some systems, the largest ~1.5 TB. We use san disks from HDS, stuck to containerfiles ~10GB size. We don't see any performance degradation in disk i/o after the conversion. Due to the size of the DB we moved data from BTABD and BTABI to 4 new tablespaces.

/Morten

Message was edited by: Morten Birch-Jensen

[torsten_ziegler]

Hello,

the number of tablespaces should not make a difference to your performance. You can cut down on the number of tablespaces if you like; on the other hand there is only very little administrative benefit in fewer tablespaces (unless you extend manually and don't let DB2 auto resize do that work for you).

One downside of fewer tablespaces is that you will approach the tablespace size limit faster. This problem is gone with DB2 9 but as long as you are on V8 you may want to project your future growth first to see if you could get in trouble there.

The new SAP proposed standard-layout is to stripe all tablespaces across all sapdatas to achieve best disk i/o utilization. In such a layout the number of tablespaces does not matter for performance at all - they become just logical groups of objects on the same disks.

Regards,

Torsten

[Former Member]

Hello,

if you reduce the number of tablespaces, you should increase the number of containers for each tablespaces to prevent further problems.

Regards,

Alexander Türk