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Home -> Community -> Usenet -> c.d.o.misc -> Re: HELP! Need Archivelog Info
Thomas Kyte (tkyte_at_us.oracle.com) wrote:
: Archive log mode is IO heavy. It doesn't use any measurable CPU time. Its a
: copy. If you started IO bound, this will make it worse.
:
: In the 'ultimate' world you would have at least 4 controllers and a device
: on each. [...]
:
: If you are IO bound, you must do something to relieve that. I turned on
: Archive log mode on my database (I generate about 500-750meg of log a day)
: and took no measurable hit (and I don't have the 'ultimate' system. One
: fast wide scsi controller but 6 disks. I can prevent lots of thrashing that
: way, keeping the heads positioned on the disks in the right place).
I'm relieved to hear that archive logging isn't supposed to be as bad as it's been for us. We do want performance, but I want data integrity first.
: what does your system look like?
The data, redo and archive logs are on a single RAID 5. I just inherited all this, so am not certain how (or whether) the load is distributed across the RAID component disks.
My first priority in all this is locating appropriate benchmarks for tuning. Our primary application is complex, so while the goal is for it to run fast, I'm not confident in using it directly as an optimization target.
Thanks for the advice. It's a rare pleasure to hear from someone on Usenet who's both knowledgeable and generous with it! I really appreciate it.
-- | Dave Schweisguth CuraGen Corp., Bioinformatics Dept. | | dcs_at_proton.chem.yale.edu New Haven, Connecticut | | http://home.earthlink.net/~dschweisguth/ My opinions are my own. | | For compliance with the NJ Right to Know Act: Contents partially unknown |Received on Thu Aug 14 1997 - 00:00:00 CDT