I am getting absolutely dreadful iowait stats on my disks when I am trying to install some applications.
I have 2 physical disks on which I have created 2 separate logical volume groups and a logical volume in each. I have dumped some stats as below
My dual core CPU is not being over utilised - 30 to 40% utilisation but the disk i/o wait is in the 70 to 80% range.
Any ideas of what could be degrading disk performance so ?
[root@ebiz1 ~]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
71609640 50967164 16946248 76% /
/dev/mapper/VolGroup01-LogVol03
721077416 35042564 649406168 6% /u01
/dev/hdc1 101086 11871 83996 13% /boot
tmpfs 1545640 0 1545640 0% /dev/shm
[root@ebiz1 ~]# sar 5 5
Linux 2.6.18-128.el5 (ebiz1.northgate-is.com) 08/04/2009
04:34:08 PM CPU %user %nice %system %iowait %steal %idle
04:34:13 PM all 3.46 0.00 14.17 61.18 0.00 21.2 0
04:34:18 PM all 3.23 0.00 19.40 60.12 0.00 17.2 5
04:34:23 PM all 2.11 0.00 14.08 80.75 0.00 3.0 5
04:34:28 PM all 1.14 0.00 12.31 86.55 0.00 0.0 0
04:34:33 PM all 5.99 0.00 19.98 74.03 0.00 0.00
Average: all 3.14 0.00 15.90 72.60 0.00 8.36
[root@ebiz1 ~]# vmstat -d
disk- ------------reads------------ ------------writes----------- -----IO------
total merged sectors ms total merged sectors ms cur sec
ram0 0 0 0 0 0 0 0 0 0 0
ram1 0 0 0 0 0 0 0 0 0 0
ram2 0 0 0 0 0 0 0 0 0 0
ram3 0 0 0 0 0 0 0 0 0 0
ram4 0 0 0 0 0 0 0 0 0 0
ram5 0 0 0 0 0 0 0 0 0 0
ram6 0 0 0 0 0 0 0 0 0 0
ram7 0 0 0 0 0 0 0 0 0 0
ram8 0 0 0 0 0 0 0 0 0 0
ram9 0 0 0 0 0 0 0 0 0 0
ram10 0 0 0 0 0 0 0 0 0 0
ram11 0 0 0 0 0 0 0 0 0 0
ram12 0 0 0 0 0 0 0 0 0 0
ram13 0 0 0 0 0 0 0 0 0 0
ram14 0 0 0 0 0 0 0 0 0 0
ram15 0 0 0 0 0 0 0 0 0 0
hdc 55278 62611 12423468 14122068 284273 127680 3329180 44306342 0 9170
hdd 22246 4615 999212 777089 86526 6531679 52845920 1606956424 0 12056
dm-0 116332 0 12419066 35397657 416117 0 3328936 339026889 0 9169
dm-1 113 0 904 2199 29 0 232 22845 0 3
hda 0 0 0 0 0 0 0 0 0 0
md0 0 0 0 0 0 0 0 0 0 0
dm-2 25977 0 997514 1013661 6620817 0 52966536 357126262 15 12053