slowing down archiver or more and smaller redo logs?

Hi
I need the advise of the oracle experts. I need to tune an application that generates about 600MB redo an hour. The application has a commit rate of about 25 commits per second (Please don't try to convince me that this is too high, commit rate is dictaded by application logic, I can not change it and it does not make sense to change it).
Currently I have the following setup:
Oracle 8.1.7.4.5 on Windows 2000 SP2
Data-Files on Volume E (Striped and mirrored) Redo-Groups 1,3,5 on Disk F: and G: (each RAID1) Redo Groups 2,4,6 on Disk H: and I:(each RAID1) Archive-Logs on Disk J: (RAID1)
We do force a log switch every 15 minutes (dbms_job issuing an alter system switch logfile).

We suffer (too) high log file sync waits immediately after switching log-files from Disks F/G into H/I, but not after switching from H/I into F/G.
Disks F/G and Disk J are connected to the same controller, so I believe we hit SCSI-bandwith limitations while the archiver is copying the last redo to J (takes about 15 secs to copy 150 mb) while LGWR needs to constantly write to H/I.
Unfortunately I cannot put in a third controller. This leaves me two choices:
a) Slow down the archiver to eat less bandwith. b) Force log switches at a higher interval, therefore reducing the amount of data the archiver has to copy in a chunk, but at the same time generating more checkpoints. As I understand, Oracle's lazy checkpointing makes this feasible.

Finally I get to my questions:
- can the archiver be configured to slow down? If so which parameters
would you suggest?
- do you think it would be ok to switch the log files every minute?

Thanks for any advise.
Marcel Received on Thu Sep 19 2002 - 13:51:45 CDT