Oracle Database 11gR2 (126.96.36.199) LGWR blocking sessions, Performance very slow
Posted on 2013-06-19
this is a call for all Oracle & Solaris Experts out there.
Currently I'm expiriencing a very strange issue on a quite large Oracle DB installation, running on Solaris 10 x64.
- HP Z420 Workstation
- 16GB RAM
- Adaptec 7805Q RAID Controller (6x 1TB VelociRaptor, 2x 512GB SSD MaxCache, RAID6)
- Solaris 10 x64 (01/13)
- Oracle 11gR2 (188.8.131.52)
I did install the DB, following the best practises guides for Solaris Installations using a ZFS store.
The oracle user has been exclusively deeded 12GB RAM, SGA_TARGET parameter was set to 10GB, SGA_MAX_SIZE to 12GB.
For the ZFS mount, the usual Performance practises have been followed, like blocksize=4K, logbias=througput, compression=off, primary_cache=all.
Even that, we are expiriencing that after about 60 minutes of running the LGWR process comes up and blocks all kinds of other sessions, performance drops below the carpet and all Advisors start reporting bad I/O performance.
I already did attache some more Redo-logfiles to the DB, it helped, but just very little.
We also tried filesystem performance checks, showing a max performance of 900MB/sec. I know this is not how Oracle is using the FS, but it gives an introduction about the system's usual performance.
Thank you very much for any help