We had Oracle 8.1.7.0 running on HP-UX 11.0 connected to FC60 Disk
Array which has 256 MB controller cache. On that system , we were
experiencing I/O issues (CPU spending more time in WaitI/o).So we
decided to shift to EMC2 having 1GB controller cache & faster disks.
We connected another machine of same configuration (except lesser
memory . New system has 3 GB RAM instead of 3.5 GB ).
We installed 8.1.7.0 on new machine.
Applied patch for 8.1.7.4
Created tablespaces as LMT's with Uniform Extent Size.Previously we
had Dictionary Managed Tablespaces.
Created users & tables with PCTFREE=10 PCTUSED=85
Exported old instance & imported it to new one with "ignore=y". We did
it per user basis.
WIth this , we were successful in removing fragmentation for tables.
All this was done on May 25. Since then we are experiencing
performance degradation. This occurs especially for Write operations.
We are even getting slower response than previous system which is
never expected. When we looked at SAR o/p , Wait I/o was almost
eliminated. But CPU tends to be busy during peak times with more than
30% of time in SYS activities as opposed to 20% on old server. Also
Load on Machine has dramatically increased to 7-8 against 3-4 (as seen
in TOP o/p). This is Production Database.
Users are getting mad over this & so are we.
I saw Waitss on 'db file scattered & sequential read' in
v$seesion_wait constituting almost 90%
