Idle time using sar is 0

[Kathleen]

What are some things I can check for this?System is responding slower than normal for login, bdf and some other things. Sar shows idle time is 0 and the rest of the output is listed below....
10:02:18 %usr %sys %wio %idle
10:02:22 13 10 78 0
10:02:26 18 13 69 0
10:02:30 13 10 77 0
10:02:34 15 14 71 0
10:02:38 10 8 82 0
10:02:42 7 8 85 0
10:02:46 20 12 68 0
10:02:50 10 9 81 0
10:02:54 17 19 63 0
10:02:58 10 11 79 0

Average 13 11 75 0

[Vijeesh CTK]

hi

idle time 0 means ur CPU is 100% utilised fm sar o/p it is is teling some process is waiting for IO/ so please check what is the process which is using CPU using 'top'
if ur having glance it will give good picture

CTK

[Mark Greene_1]

You are I/O bound. What sort of disk is on the system, an array or JBOD? Are you seeing any disk related errors in the syslog?

Do an "iostat 1 5" to see which disks are getting pounded. You may have a run-away application process. If your system is hosting a database, you may have had someone doing a large query, or perhaps they typo'd the input and are selecting a data range that includes all the data in the tables they are querying against instead of just a subset.

HTH
mark

[A. Clay Stephenson]

Simply run 'top' and look for the hogs. You may simply have a very busy system or you may have a few runaway processes.

[Helen French]

Hi Kathleen:

The idle time 0% means the system CPU is fully utilized this time. The sar output shows a high I/O waiting too ! I would suggest you to check the system with GlancePlus:

# gpm

Also run 'top' for better process/process status. These are the tools which you could use:

# top
# vmstat
# swapinfo
# sar -d 1 10

HTH,
Shiju

[Kathleen]

The output of top is attached....

[Kathleen]

The output of
# vmstat
# swapinfo
# sar -d 1 10

is attached....

[Sanjay_6]

Hi Kathleen,

The top output you have attached is the first page only. There are 54 more pages like that.

Hope this helps.

Regds

[Vijeesh CTK]

hi

Now the top o/p is showing normal. nothing extraordinary.this time i assume that your system is working fine.

see what you have to do is when u feel that ur system is really slow. just check the again the top output and do a sar -u 1 100 so that you can find out what is the process which is loading the CPU (waiting for IO).

CTK

[Bill Hassell]

The output of top shows that the machine is barely being used. That's the problem with simple tools like top or sar--they take a snapshot of a very complex system and for the picture given in the top output, the system is 25% idle. Now it does indicate 40% system overhead which is directly related to I/O and other system calls but no classic Unix tools will show this data very well.

The original sar output with 0% idle may have meant that 2-3 users all decided to run du / at the same time, causing massive I/I ans system overhead to calculate disk usage.

You really need a better tool like Glance to show you what the system is really doing. It's on your Application CDs.