I'll check with the DBAs on that.
I'm looking at the replication target filer and it's actually even worse, with cp_reads almost matching user_writes on the physical disks. The replication method is dataguard.
________________________________ From: "Steiner, Jeffrey" Jeffrey.Steiner@netapp.com To: Fred Grieco fredgrieco@yahoo.com; "Toasters@teaparty.net" Toasters@teaparty.net Sent: Friday, September 13, 2013 2:21 PM Subject: RE: high CP_reads/writes ratio
That sounds strange. An aligned Oracle database ought to be doing whole block writes under all circumstances, with the exception of a tiny amount of CP read behavior with the archive and redo logs. You can occasionally get into trouble with SAN filesystems where the block size of the filesystem itself results in misalignment, but not here. Can you share the load average and top 5 wait events section of a one-hour AWR report encompassing this 15 minute cycle so we have an idea what kind of IO is occuring and the latencies you are experiencing? From:toasters-bounces@teaparty.net [mailto:toasters-bounces@teaparty.net] On Behalf Of Fred Grieco Sent: Friday, September 13, 2013 8:07 PM To: Toasters@teaparty.net Subject: high CP_reads/writes ratio What kinds of things can cause a high CP_reads/writes ratio? And what can I do about it?
I have an Oracle system with ASM that doing writes in a 15 minute cycle, and it causes a lot of writes with CP reads. The oracle ASM luns are basically the only thing on the aggregate. Disk alignment is fine (which is the first thing I thought of). I've attached a screenshot of the Oncommand graph for one of the disks in this aggr-- not sure if that will come through.
The filer is a 3220 with 8.1.2 7-mode. Fibre channel attach, and there are about 20 luns under two volumes.
TIA,
Fred
