We are in the process of migrating to a new AIX server
environment, with two RS/6000s configured thusly:

Hardware: F50 RS/6000
          4 166MHz PowerPC 604e
          512MB RAM
          3 4.5GB SCSI internal disks

          16 9.1GB SCSI disk in two SSA loops

We are in the process of defining the logical volumes upon which
the database will reside, and we are interested in hearing the
experiences of others.

Our current plan is to configure eight (8) SSA drives per server,
using four (4) for the database and log volumes, and the other
four (4) for database and log copies. We plan to create four (4)
8GB logical volumes across each set of four SSA drives, and one
(1) 4GB logical volume across the same set of drives. The 8GB lvs
will be for database volumes and dbcopies, and the 4GB lvs will
be for log volumes and logcopies.

We are initially considering a 64KB stripe size for the logical
volumes, but I would like to know if others have experience with
different stripe sizes, and what type of performance they see
with their SSA devices. In initial tests, we were only able to
read from the disks (when using a block device) at a rate of
4MB/s. Tests when reading from a character device are nearly
seven times that rate (~28MB/s). Obviously we'd like to be much
closer to the latter numbers than the former.

I'd also be interested in hearing how people have configured
their virtual memory parameters, particularly with respect to how
they relate to the BUFPOOL parameter for your ADSM server.

Any hints, tips, war stories, or pointers to further
documentation for performance tuning of this nature are gladly
accepted.

Thanks. -- Tom

"It's a dog eat dog world,                Thomas A. La Porte
 and I'm wearing milkbone underwear."     DreamWorks SKG
              - Norm Peterson             <tlaporte AT anim.dreamworks DOT com>