Performance on Solaris 10 - Operating system paging

Question

Has anyone experience performance issues after an upgrade from Solaris 9 to Solaris 10 on SAP systems with limited memory?
We have many systems that are on servers with 4 Gig of memory and ran well on Solaris 9.  After an upgrade to Solaris 10 we are experiencing very high OS system paging rates.  The response times of the SAP systems are very poor when this occurs.  It seems to take very little load to cause this.
I realize more memory or decreases in Oracle or SAP memory parms will solve this but am wondering if there is anything on the Solaris OS that could resolve this?
Thanks,
Dan

Answer 1

DISM can be used but in global zone only (according to Sun document "Best Practive for Running Database in Solaris Containers" , the  proc_lock_memory privilege which is required to run the ora_dism_ process is not available in non globale zone)
The doc i got is from 2005, so don't know if the Sun recommendations has been updated since then.
In order to activate DISM (if you are in a global zone), sga_max_size should be set up larger than the sum of sga components: db_cache_size, shared_pool_size ...)
Also look for the Sun Blueprint "Dynamic Reconfiguration and Oracle 9i Dynamic Resizable SGA" on http://www.sun.com/blueprints
If you use ISM because in a non-global zone, you can use oracle parameter lock_sga to ensure the SGA is loaded into the RAM and useism_for_pga = true to ensure PGA is loaded into the RAM.
Make sure you have enough RAM to hold filesystem cache (OS memory) , oracle memory, and applications memory
Make sur your PGA and SGA are correctly sized size, since you won't be able to dynamically change the ISM allocation. (see v$shared_pool_advice, v$db_cache_advice, v$pga_target_advice ...)
Take the usual precautions:
- have a successfull backup first
- do the change on a test machine
- and/or ask your vendor before proceeding
Other Doc to read ...
Note 697483 - "Oracle Dynamic SGA on Solaris"  (recommends to read Sun doc n°230653)
Note 724713 - parameter settings for Solaris 10, here is an extract :
Only one parameter from SAP note 395438 should remain in file
etc/system
set rlim_fd_cur=8192
As described in SunSolve document 215536, the "Large Page Out Of the Box" (LPOOB) feature of the Solaris 10 memory management, first implemented in Solaris 10 1/06 (Update 1), can lead to performance problems when the system runs out of large chunks of free contiguous memory. This is because the Solaris 10 kernel by default will attempt to relocate memory pages to free up space for creating larger blocks of contiguous memory. Known symptoms are high %system CPU time in vmstat, high number of cross calls in mpstat, and Oracle calling mmap(2) to /dev/zero for getting more memory.
Memory page relocation for satisfying large page allocation requests can be disabled by setting the following Solaris kernel parameter in /etc/system
set pg_contig_disable=1
This will not switch off the LPOOB feature. Large memory pages will still be used when enough free space of contiguous memory is available, so the benefits of this feature will remain
Note 870652 - Installation of SAP in a Solaris Zone
Note 1246022 - Support for SAP applications in Solaris Zones
Edited by: Emmanuel TCHENG on Oct 13, 2009 12:02 PM