Operating System - HP-UX
1748104 Members
4531 Online
108758 Solutions
New Discussion юеВ

Re: Performance problems with IBM universe

 
albcantabria
Occasional Advisor

Re: Performance problems with IBM universe

MFILES goes to 936, but we have others systems with similar capacity and workload, but not HP. And performance seems to be better.
Any possible problem with vxfs, volume configuration o kernel paramters could be the problem?.
Any idea is appreciated.
Regards.
albcantabria
Occasional Advisor

Re: Performance problems with IBM universe

Logical vol have been defined like mirrors as follows
Mirror policy: strait
consistency: no
sched: parallel
write cache: yes
extend size=32
mode:read/write
it is a good configuration for Universe?.

And, is ussual than iostat shows different rates for identical disks in mirror:

bps sps msps
c0t6d0 1739 1644 1
c3t6d0 2017 1773 1

Bill Hassell
Honored Contributor

Re: Performance problems with IBM universe

Check the sar -a stats. This is a measure of directory activity (open/close). Run the command when the system is busy:

sar -a 1 10

iostat is almost useless today since disks are no longer simple devices (hardware buffering, array controllers, stripes, etc). That's the reason that msps is always 1.

You can't compare different systems without defining the actual work being performed. I have regularly seen 5 to 50 times more I/O per task for "similar" systems. An investigation into the actual I/O (data read/write, directory open/close, buffer cache, MFILE settings, missing or corrupt indexes, etc) all affect the number of I/O's being generated. If you do not see any errors in syslog, then the hardware is doing what it was told to do.


Bill Hassell, sysadmin
albcantabria
Occasional Advisor

Re: Performance problems with IBM universe

Buffers, swap, inode seem to be ok (sar results).
My doubt is about times of devices.

Avserv (and avwait) is sometimes very high
(avserv Average time (in milliseconds) to service each transfer request (includes seek, rotational latency, and data transfer times) for the device)


HP-UX dmsreae1 B.11.11 U 9000/800 04/05/06

12:49:45 device %busy avque r+w/s blks/s avwait avserv
12:50:15 c0t6d0 100.00 2.93 150 2742 26.12 26.99
c3t6d0 97.00 2.69 145 2952 25.26 24.49

I can see also it via sar -u. High wio times.

12:49:45 cpu %usr %sys %wio %idle
12:50:15 0 14 15 29 42
1 15 10 63 12
2 9 4 51 36
3 9 12 24 55
system 12 10 42 36

Any idea?. Best regards.