Different performance
Olt, Joseph
jolt at ti.com
Mon May 12 12:11:12 UTC 2008
Tina,
How are the partitions laid out on the two systems? It is likely that
something OS related is accessing sda and sdb or host 1 while being
spread across more disks in host 2. From the output of host 2 you
provided, the first stat shows sdc is taking some of the load.
Regardless of the RAM being the same in both systems, is there much
swapping? Swapping on higher performance drives will be quicker.
Regards,
Joseph
________________________________
From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Tina Tian
Sent: Friday, May 09, 2008 10:42 PM
To: redhat-sysadmin-list at redhat.com
Subject: RE: Different performance
The DB is Sybase ASE 15.0.2. Identical configuration on two hosts. My SA
also confirmed that two hosts are almost identical except host2(faster
DB load) has extra two disks sdc and sdd, sdc and sdd are with higer
RPM=15k. The rest of disks sda and adb are identical on two hosts,
with RPM=7k. On both host 1 and host 2, DBs are on /dev/sdb only.
Best Regards,
Tina
________________________________
To: redhat-sysadmin-list at redhat.com
Date: Fri, 9 May 2008 16:58:19 -0600
From: larry.sorensen at juno.com
Subject: Re: Different performance
Please include information on the databases including versions. It could
just be different configurations on the databases. Are the patches up to
date and equal on both servers?
On Fri, 9 May 2008 14:11:25 -0700 Tina Tian <tinatianxia at hotmail.com>
writes:
I am a DBA. I have identical database servers running on two
Linux redhat 4, host 1 and host 2. When I was running the same bulk load
to database (load a data file to database), host 2 was much faster than
host 1.
On both host1 and host2, database are using file system mount on
/dev/sda and /dev/sdb.
I checked with my SA, host1 and host2 have same CPU, RAM, file
system configuration. The only different is that host 2 has extra HD
capacity with higher 15k RPM. But the extra 2 HDs(sdc and sdd) are
dedicated to other applications, not used by database at all.
My questions are:
-----------------
1. On host2 (faster), the extra faster HDs(/dev/sdc and sdd) are
not used by database. Does it still affect IO performance of /dev/sda
and /dev/sdb ?
2. During database bulk load testing, host 1(slower) shows
longer service IO time (svctm) and longer IO waiting time(await).
What other possible reason can cause this problem? Any idea?
I did post the same issue to database discussion group and they
suggested me to check OS performance(svctm).
Below is the result from iostat on host1(slower) and
host2(faster) during bulk load:
Host 1: iostat -x 2
=====================
avg-cpu: %user %nice %sys %iowait %idle
0.15 0.00 0.07 0.28 99.49
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.01 0.59 0.24 0.19 29.22 6.17 14.61
3.08 83.49 0.01 21.71 3.84 0.16
sdb 0.04 10.05 0.89 3.74 117.37 110.34 58.69
55.17 49.13 0.10 21.76 4.48 2.08
avg-cpu: %user %nice %sys %iowait %idle
15.74 0.00 8.99 0.31 74.95
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 1.99 0.00 57.71 0.00 14025.87 0.00 7012.94
0.00 243.03 0.21 3.58 3.53 20.35
sdb 0.00 0.00 11.94 0.00 95.52 0.00 47.76
0.00 8.00 0.02 2.04 2.04 2.44
avg-cpu: %user %nice %sys %iowait %idle
6.18 0.00 2.37 9.24 82.20
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.50 0.50 23.00 1.00 5732.00 12.00 2866.00
6.00 239.33 0.07 3.08 3.02 7.25
sdb 0.00 129.00 7.00 130.00 56.00 2076.00 28.00
1038.00 15.56 0.75 5.49 5.40 73.95
avg-cpu: %user %nice %sys %iowait %idle
0.06 0.00 0.12 12.44 87.38
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 3.50 0.00 3.00 0.00 52.00 0.00
26.00 17.33 0.03 10.00 3.67 1.10
sdb 0.00 182.50 0.00 182.50 0.00 2920.00 0.00
1460.00 16.00 0.99 5.44 5.44 99.30
avg-cpu: %user %nice %sys %iowait %idle
0.00 0.00 0.12 12.49 87.38
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.50 0.00 1.01 0.00 12.06 0.00
6.03 12.00 0.01 6.00 6.00 0.60
sdb 0.00 184.92 0.00 185.43 0.00 2962.81 0.00
1481.41 15.98 1.01 5.45 5.38 99.70
avg-cpu: %user %nice %sys %iowait %idle
0.00 0.00 0.06 12.43 87.51
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
sdb 0.00 184.08 0.00 184.08 0.00 2945.27 0.00
1472.64 16.00 0.99 5.39 5.38 99.00
avg-cpu: %user %nice %sys %iowait %idle
0.00 0.00 0.12 12.31 87.56
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 1.00 0.00 1.50 0.00 20.00 0.00
10.00 13.33 0.02 15.33 6.67 1.00
sdb 0.00 181.00 0.00 181.00 0.00 2896.00 0.00
1448.00 16.00 0.99 5.48 5.49 99.40
avg-cpu: %user %nice %sys %iowait %idle
0.00 0.00 0.19 12.37 87.45
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
sdb 0.00 178.00 0.00 178.50 0.00 2852.00 0.00
1426.00 15.98 1.00 5.61 5.55 99.10
avg-cpu: %user %nice %sys %iowait %idle
0.00 0.00 0.12 12.37 87.51
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
sdb 0.00 179.50 0.00 179.50 0.00 2872.00 0.00
1436.00 16.00 0.99 5.52 5.53 99.25
avg-cpu: %user %nice %sys %iowait %idle
0.00 0.00 0.06 12.44 87.50
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 1.50 0.00 3.50 0.00 40.00 0.00
20.00 11.43 0.07 20.00 4.00 1.40
sdb 0.00 179.00 0.00 179.50 0.00 2868.00 0.00
1434.00 15.98 1.02 5.68 5.53 99.30
avg-cpu: %user %nice %sys %iowait %idle
0.06 0.00 0.19 12.41 87.34
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.50 0.00 1.00 0.00 12.00 0.00
6.00 12.00 0.01 6.50 6.50 0.65
sdb 0.00 183.50 0.00 183.50 0.00 2936.00 0.00
1468.00 16.00 0.99 5.40 5.41 99.25
Host 2: iostat -x 2
==================
avg-cpu: %user %nice %sys %iowait %idle
0.96 0.00 0.69 0.21 98.15
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
hda 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 48.00 0.00 1.33 1.33 0.00
sda 0.01 5.31 0.23 1.55 17.96 54.93 8.98
27.47 40.76 0.07 41.59 1.21 0.22
sdb 0.03 3.99 0.84 0.47 113.52 35.67 56.76
17.83 114.36 0.03 23.00 2.55 0.33
sdc 0.05 37.80 0.58 1.50 131.96 314.37 65.98
157.19 214.93 0.43 205.85 2.84 0.59
sdd 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 40.35 0.00 3.52 3.52 0.00
avg-cpu: %user %nice %sys %iowait %idle
16.03 0.00 8.61 0.44 74.92
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
hda 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
sda 1.99 14.43 57.71 6.97 13775.12 171.14 6887.56
85.57 215.63 0.22 3.43 3.36 21.74
sdb 0.00 357.71 7.96 358.71 63.68 5731.34 31.84
2865.67 15.80 0.04 0.10 0.10 3.83
sdc 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
sdd 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
avg-cpu: %user %nice %sys %iowait %idle
15.62 0.00 8.81 0.56 75.00
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s rkB/s
wkB/s avgrq-sz avgqu-sz await svctm %util
hda 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
sda 1.50 0.00 56.00 0.00 13964.00 0.00 6982.00
0.00 249.36 0.22 3.90 3.89 21.80
sdb 0.00 635.00 7.00 635.00 64.00 10160.00 32.00
5080.00 15.93 0.06 0.09 0.09 5.55
sdc 0.00 1.00 0.00 1.50 0.00 20.00 0.00
10.00 13.33 0.00 0.00 0.00 0.00
sdd 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00
Thanks,
Tina
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