Re: RAID10 config...

If you already have this system set up, then can you look at your I/O stats to see how busy things are? You'll have to go to the OS level to get I/O stats on the drives that have your redo, archivelogs, controlfiles.

> However, since the OS+SW won't create much load,
> I could in theory put the archivelogs there too:
> 1 pair OS,SW,archivelogs (+ 2 controlfile)
> 1 pair redos
> 2 pairs or 1 quadruple for datafiles

Typically, I don't like putting OS+SW on the same device as other things, but one has to make do with what they have. So you might want to investigate putting archived logs, or maybe some of your datafiles on that device. Like I said, I don't like it but it may be necessary to distribute your workload among only four devices.  

> Am I right in assuming that during writes, controlfiles
> become bottlenecks?

My control files are the biggest bottleneck, not even close. Online redo logs, archive log destination, and the datafiles belong the the tablespace being loaded are the ones that get the most activity when I do mass loads of data.

> Would it more sense to spread out the datafiles or the
> redos?

Both. But may not be possible in your situation.

> The lamps on my redo disks are almost constantly
> on during our load runs but I imagine that only small
> portions are written each time.

That tells me that your redo logs are getting hit pretty heavily. This will probably be shown in your sar logs.

> The statspack says 1,804.45
> per transaction, 124,352.33 per second, I suppose it's bytes.

IIRC, it is bytes.

> Also log file sync and log file parallel write together take up 55%
> of the % total elapsed time in the top 5 timed events of my
> statspack report. (db file parallel write are another 13%)

Another indicator that your redo logs are getting hit pretty heavily.

> The problems I see are basically, how to distribute the controlfiles
> and how to make redo writes faster, given 8 disks.

Get more disks!! LOL. Why can't you hang more disks on your system?

HTH,
Brian

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Brian Peasland
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