incredibly overloaded disk subsystem

per MS, disk queue length values as measured by PerfMon on Win2K should be
very low (1-2), or you're experiencing I/O issues.

well, we have an app powered by an Oracle database that's constantly getting
hammered. We routinely measure queue lengths in the hundreds on up to the
6,000-7,000 range. As you might imagine, our app works very poorly & we
have lots & lots of problems. I'm convinced it's the database I/O that
kills us, to the point that it's what makes our com servers that talk to it
fail, things like that.... like requests are just getting blocked, that sort
of thing.

is this reasonable? has anyone ever done any sort of study that indicates
odds of failure as you push the hardware well beyond its limits? We have
two of Dell's high-end controllers powering this (PERC3/DC pushing two RAID1
sets for archive logs and another PERC3/DC powering a RAID10 set for
database). The OS (Win2K AS SP4) is on another separate RAID adapter. I'm
convinced there is nothing we can do to help ourselves until we remove this
bottleneck, & i also believe we are putting ourselves at serious risk of
catastrophic failure with our current system.

i appreciate any thoughts.

thanks

"aDF" wrote:
well, we have an app powered by an Oracle database that's constantly
getting
hammered. We routinely measure queue lengths in the hundreds on up to the
6,000-7,000 range. As you might imagine, our app works very poorly & we
have lots & lots of problems. I'm convinced it's the database I/O that
kills us, to the point that it's what makes our com servers that talk to
it
fail, things like that.... like requests are just getting blocked, that
sort
of thing.

First, make sure that Oracle works smoothly. A misconfigured Oracle database
can generate a LOT of I/O.

Go to http://oracle.oreilly.com/ Choose "Optimizing Oracle Performance".
Read the sample chapter. Buy the book and read it or contact a reputable the
Oracle tuning company (eg. the company the author works for). Tune database.

When you know that Oracle is tuned, then you should consider everything
else.

greetings,