very poor performance, prealloc command

[Rajeev jain]

q_depth is set to 255 with no help. I will check the parameters on Storage.

[Rajeev jain]

I would highly appreciate if anyone could post me the result from two commands below, one from local drives and SAN drives. Please list your hardware model at the high level.

$ timex prealloc test $((1000*1024*1024))
$ timex cp test test1

This will help me a ton. I am leaning towards hardware issue as well but having tough time getting through.

[Patrick Wallek]

Here you go:

Hardware -- HP9000 rp5470 - HP-UX 11.11
Local Drives:
[ root@hquwh01:/home/root ]
# timex prealloc testxxx $((1000*1024*1024))

real 1:40.34
user 0.13
sys 6.56

[ root@hquwh01:/home/root ]
# timex cp testxxx testxxx1

real 1:42.50
user 0.04
sys 12.60

[ root@hquwh01:/home/root ]
# ll testxxx testxxx1
-rw------- 1 root sys 1048576000 May 29 15:25 testxxx
-rw------- 1 root sys 1048576000 May 29 15:27 testxxx1
[ root@hquwh01:/home/root ]
#


SAN Drives (VA7400 - 1Gb/s Fibre):
[ root@hquwh01:/sync ]
# timex prealloc test $((1000*1024*1024))

real 31.88
user 0.12
sys 7.99

[ root@hquwh01:/sync ]
# timex cp test test1

real 53.71
user 0.04
sys 13.91

[ root@hquwh01:/sync ]
# ll test test1
-rw------- 1 root sys 1048576000 May 29 15:32 test
-rw------- 1 root sys 1048576000 May 29 15:33 test1
[ root@hquwh01:/sync ]
#

[Patrick Wallek]

And here's from another, slightly newer, system:

HP9000 rp4440 - HP-UX 11.11:

Local disks:
[ root@tnudb05:/usr ]
# timex prealloc test $((1000*1024*1024))

real 1:21.00
user 0.07
sys 2.78

[ root@tnudb05:/usr ]
# timex cp test test1

real 1:35.12
user 0.02
sys 5.52

[ root@tnudb05:/usr ]
# ll test test1
-rw-r--r-- 1 root sys 1048576000 May 29 15:35 test
-rw-r--r-- 1 root sys 1048576000 May 29 15:38 test1
[ root@tnudb05:/usr ]
#

SAN Disks (VA7410 - 2 Gb/s fibre):
[ root@tnudb05:/dump ]
# timex prealloc test2 $((1000*1024*1024))

real 12.06
user 0.07
sys 3.35

[ root@tnudb05:/dump ]
# timex cp test2 test3

real 25.05
user 0.02
sys 5.42

[ root@tnudb05:/dump ]
# ll test2 test3
-rw-r--r-- 1 root sys 1048576000 May 29 15:41 test2
-rw-r--r-- 1 root sys 1048576000 May 29 15:42 test3
[ root@tnudb05:/dump ]
#

[Dennis Handly]

>Hein: did truss show alternating writes and fsyncs, or one fsync at the end?

In my first reply I said, at the end.

>And how large were the IOs?

I also said: writes 8Kb (the filesystem blocksize)

And that was my blocksize.