Re: HP AutoRAID question....
In article <34fc9cfe.90032039@10.209.30.200>,
jharris@westpac.com.au (Jason Harris) wrote:
>Billy,
>
>The main thing have noted on HP performance is that KAIO is slower
>than AIO VPs. But AIO VPs use a lot more CPU resources than KAIO. For
>example an archive on KAIO shows very little CPU usage, about 10% of 5
>CPUS whereas using the AIO VPs uses 50% of three CPUs plus 5 - 10% of
>the other two.
>
>Which are you using? If the CPU % used is very low then check the IO
>queue info ie onstat -g ioq and onstat -g iov.
>
>We also are using AutoRAID.
>
>Jason
>
Jason and Billy,
One thing I have noticed is that Informix seems to be EXTREMELY sensitive
to minor configuration differences on HP platforms. We are an HP9000
shop, have been for 8 years. I have configured and installed Informix
on HP G, H, K, D and (soon) V class systems, starting with version 4 of
Informix running under HP/UX 9.0x to 7.21.uc3 running on 11.0. I have
never found the same kernel parameters to work as expected with each
move. Most of these systems used lots 'o little disks (25 X 2 gigabyte
FS SCSI typically). On some systems, KAIO ran as much as 20% faster than
AIO VPs did. On other systems, AIO was faster. On some systems, fragmenting
tables across a bunch of small spaces worked best, on other systems dumping
the whole damn thing, indexes and all, into one big chunk worked best.
On some systems, huge amounts of read ahead pages sped things up; on other
systems, made no difference at all. On some systems, multiple CPU VPs, even
to the extent of several more than physical CPUs, worked best; on others,
one CPUVP ran fastest. Keep in mind this is the same damn database, simply
unloaded and loaded as the boxes grew. Same indexing strategy, same relations,
same data, with mucho experimentation on each implementation regarding
fragmentation strategy and kernel tuning.
Just about the only absolutes I've found: move the logical log, physical log
and root database spaces onto their own drives, preferably the internal
FS SCSI II. Never found a RAID configuration that worked nearly as well
as a bunch of small disks. Always configure several temp spaces, each on
their own physical device; I never use fewer than four (sorting speeds up
dramatically!)
If anyone else out there has found HP UX and OnLine to be as persnickity
as I have, would enjoy hearing your story.
Ray Garrison