Re: DB File Sequential Read Waits

ripfal,
What's the EMC model that you have ? is it a symmetrix ? Are you using any volume manager on top of EMC ? In DB File Sequential Read Waits the thing to look for is the average wait. In your case it seems a bit high at 39ms. I have seen an average of upto 8 ms on some boxes.
Also It is always recommended to use striped metas for your data and index discs. You can use concatenated metas for your archive log destinations.
Where did you place your redo logs ? a log file sync of 13 ms in your case is also a bit on the higher side.
Whats the total hard disk capacity that you put on your FA port ? That will also have an impact on the I/O. What SAN switch do you use and have you applied all patches for it ?

As far as the database is concerned,
It would have been good if you had enclosed a statspack report for a 20 minute duration. Are you running any long batch jobs in your instance ?
During the period of collection, i think several long running operations have ended.
Your hard parse ratio is horrible.
Did you do any customization ? I think your developers are not using bind variables.
I think You could have also benefited from Locally Managed Tablespaces.
How many copies of control files do you have and where did you place them ?

By the way what was going on in the instance while you collected the stats?
I think you can set your sort_area_retained_size also to 1M (the same as your sort_area_size).

regards
Srivenu Received on Tue Dec 30 2003 - 01:14:01 CST