Re: General SAN advice needed for 2TB 9.2.0.8 database on HP-UX

> So even though Oracle recommends putting everything on the same
> stripe, you still separate the log files? Have you noticed any
> performance gains from doing this from your testing?
>
> The thing is that being able to write out log files across an 8 disk
> stripe means much faster write times if the IO isn't being chugged
> down by other processes.

You have to test in your own environment and measure what different setups work better or not so much. As I noted my systems are OLTP databases with some very commit happy applications ( commit too much ... like on every row often ).

The one size fits all recommendations are generic ones that may or may not make sense. Like I noted I get an average of less than 1 ms for log file sync ... that is the wait event I tune for on the online log files.

I am also using for my most important prod systems RAID 1 for the LUNs for the log files and RAID 1+0 for the rest of the database portions ( again using ASM for both ). Any competent storage array buffers the write activity in cache.

For test databases and our datawarehouse systems we are using RAID 5 ... not my prod OLTP systems.

Yes you have to do a lot of work to try different setups and write different things to simulate different kind of workloads. Custom designed tests take a lot of time but things that go after your important tables in ways that ( somewhat ) simulate your real applications give better and ( hopefully ) more reliable performance numbers than generic testing tools that are available. Received on Fri Jun 25 2010 - 05:37:58 CDT