Re: Kernel parameter recommendations for HP-UX 11.11 in regard to SGA size

On Jun 9, 3:57 pm, hpuxrac <johnbhur..._at_sbcglobal.net> wrote:
> On Jun 8, 5:44 pm, joel garry <joel-ga..._at_home.com> wrote:
>
> > That was very helpful, thanks. Except for the part about archiving
> > being turned off! From what I've seen, that's one of the bigger users
> > of I/O, with a much different profile than regular datafile
> > operations.
>
> Well the archive process just copies redo logs to archive logs
> possibly multiple copies. You can always test that part as you need
> to.
>
> Confused about your "the bigger users of I/O" statement ... log file
> sync is time critical for active transactions. Copying the redo logs
> after they switch just doesn't have that type of critical emphasis
> unless you are filling up online redo logs faster than you can archive
> them.

It normally isn't critical, but in a SAME sort of configuration under heavy loads (like loading a major schema) with RAID-5, the heavy sequential write of the copy can become critical (slowing everything down without necessarily stopping because it can't archive). Minor point to keep in mind the next time someone offers up an article about how RAID-5 really isn't that bad.

jg

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