HP-UX equivilant of AIX max_coalesce parameter

[Kim_18]

Does anyone know if there is an hp-ux equivelant to the AIX max_coalesce parameter. This parameter indicates the size of the data block sent to the disks.

[RAC_1]

What exactly this AIX parameter does??
HP-Ux has file system block size. You can check it with fstyp -v /dev/vgxx/lvolx
df -g /mount_point

Anil

[Kim_18]

the max_coalesce parameter is aix defines the size that the hardware i/o driver uses to packet data before sending it to the storage subsystem

[Bill Hassell]

This is actually variable within the kernel and not set to a fixed value. Actual buffers may be 128k to 256k, possibly more depending on the OS version and patch level.

[Kim_18]

We are actually seeing only 32K going to our EMC storage system even though the stripe size is 128K. Where is this in the kernel - how can I look at this. We are at hp-ux 11.0.
We saw this same thing in AIX and had to change the max_coalesce parameter which defaulted to 32 and bumped it up to 128K, therefore we thought the same thing might exist in HPUX.

[FERRARI MARCO]

Did the parameter vastly change the throughput ?
We've got both type of servers and I don't remember having set it when ( before 2002 ) I was working on AIX.
Should be great for bulk insert/select but how about transactional workload ?
TIA,
Marco

[Pat Lieberg]

I remember doing this same thing with EMC storage when I was working with AIX and it made a big difference for us. The system was a 7.2TB data warehouse.

You can check this link for info on tuning VxFS.

http://docs.hp.com/en/B7961-90025/ch12s04.html

The vol_maxioctl paramter might be close to what you want, but I haven't done enough tuning or reading to be sure.