check if the disk is slow

UNIX for Advanced & Expert Users
1

Hi,
we have some Oracle DBs on a AIX server.
We have the following error messages :

Warning: log write time 540ms, size 5444KB
*** 2008-05-14 10:19:02.686
Warning: log write time 1470ms, size 5533KB

Oracle in LGWR Is Generating Trace file with "Warning: Log Write Time 540ms, Size 5444kb" In 10.2.0.4 Database [ID 601316.1] metalink note says :


So probably you need to check if the disk is slow or not or for any potential OS causes. If 

everything looks fine at the hardware level or OS level then you can safely ignore these messages.

How can I check if the disk is slow or not or for any potential OS causes ?

Thank for help or any idea ?

2

Use 'sar'. Set it up as a cron job running every 20 minutes and wait a day for results.

3

I think you need to write something to listen on your Oracle error_log once the output include "Warning: log write time" then your script need to run some monitoring commands like :

vmstat 
iostat
sar

then save the output to the log file , this will help you to identify and resolve the problem as you collected the stats in realtime the error appeared.

4

Did this message appear only once back in 2008 or is it still showing up from time to time?
Does your errpt show anything for the time the problem occured?
Do you use local disks or san?

5

Hi Cero,
I have this message now. What I pasted here is from Oracle Docs.
What is errpt ?
We use san.

Thanks and regards.

6

Run iostat for a few seconds:

iostat -sndzx 1

If possible, post the output.

7

errpt is the command for the aix error-report you can use to check if the OS was involved in that problem. The tools the other posters suggested should give you a good overview of your disks performance.