Mirroring protects you from more than disk failure, it also protects you from human error. Please, mirror your logs. There is a long history littered with un-employed DBAs backing this recommendation. For your specific problem, you might want to look a a couple of things. How long does it take you to fill up a gigabyte of redo? How long does it take you to write an archive log that's a gigabyte in size? What is your log_buffer parameter set to? Have you evaluated the effect of checkpoints in your situation? On Tue, Apr 7, 2009 at 1:14 PM, Crisler, Jon <Jon.Crisler@xxxxxxx> wrote: > The redo logs are 6 groups, 2 members each, 1gb in size. The SAN is EMC > Clariion. Raid 5 does have somewhat poorer performance in writes in our > environment but its usually not a major factor. > > -----Original Message----- > From: Rajeev Prabhakar [mailto:rprabha01@xxxxxxxxx] > Sent: Tuesday, April 07, 2009 12:48 PM > To: Crisler, Jon > Cc: Oracle-L Freelists > Subject: Re: Mirroring redo log groups or not ? > > Hello Jon, > > Before you go into redesign of the redo logs, did you check w/the > SAs/Storage > Admins ? During my last interactions with type of performance issue, I > found > that RAID 5 had a negative effect on overall performance during QA > testing. of > course, your mileage may vary. > > Can you share your findings (as seen by SA/Storage Admins). How big are > your > redo logs ? What kind of disks (Storage/SAN) are you folks using ? > > -Rajeev > > On Tue, Apr 7, 2009 at 12:16 PM, Crisler, Jon <Jon.Crisler@xxxxxxx> > wrote: > > > So, if the LUN that holds the online redo logs is already protected > (raid 1, > > 5 etc) do I really need to mirror the online redo logs ? Should I > convert > > the LUN to Raid 1 / 0 ? if I convert to Raid 1/ 0 should I keep redo > log > > mirroring and point to the same LUN ? > -- > //www.freelists.org/webpage/oracle-l > > >