How to detec the process id which casue IO busy?

[Zhuang Yongliang]

Recently, Production server will down one or two times per day. When we check system, found IO is very busy when system is down, but CPU is very low, We want know which process cause IO busy? how to get the process id which cause IO busy, attachement is Sar,top, and IO stat. Any hint or reference document is appreciated. Thanks

[Vivek Bhatia]

Hi Zhuang,

Have a look at few things which i have noticed.

1. 00:00:00 device %busy avque r+w/s blks/s avwait avserv
Average c2t1d0 2.36 1.11 11 146 1.29 4.14
Average c3t0d0 0.01 0.50 0 0 0.00 2.49
Average c9t0d0 17.38 1.34 73 2746 1.69 5.36

c2t1d0 and c9t0d0 are the disk utilized . So check what filesystems do you have on these disks?

2. If you want to know about the processID utilizing the server.

Collected the information from the top output.
1. ProcessID: 1473 , process name:cimprovagt

Thanks
vivek Bhatia

[Turgay Cavdar]

Hi Zhuang,
Did your system crash? In order to find why system crashes, crash data must be analyzed.

[R.K. #]

Hi Zhuang,

c2t1d0 -- indication of jobs stacking up here as avque is consistently high.

Identify the presence of disk:
#strings /etc/lvmtab -- to identify the volume group associated with the disks.
#lvdisplay -v /dev/vgXX/lvolX -- This will tell you what disks are associated with the logical volume.
#bdf -- to see if this volume groups files sytems are full ( > 85%)
#cat /etc/fstab -- to determine the file system type assiciated with the lvol/mountpoint

Now you can check that related LV is a part of what application and why the disk usage is high.

Regds..

[Zhuang Yongliang]

This is a oracle database server, so the IO must be consumed by oracle user or system. Can we have a method to identify the IO is consumbed by system or by user? Does Sar report can provide processs id information or not? My wonder if why CPU utilization is low, but why IO is so busy? Thanks

[Javed Khan_1]

Hi,

you can find this using glance

select i/o by file system by pressing i

at the bottom of the screen you can see this info

Top disk user: PID 3219, utild 0.3 IOs/sec S - Select FS


Regards,
Javed