Buffer and Redo Nowait Ratio

Buffer Nowait Ratio

If this ratio is greater than 99%, then it indicates that the server process is able to obtain the buffer immediately.

If this ratio is less than 99%, then it indicates that the server process has to wait for something before obtaining the buffer. You must investigate the Buffer Waits Section of Statspack/ AWR report.


Redo Nowait Ratio

It indicates the percentage of time the redo space is immediately available without having to wait. A low value indicates small redo log file and frequent redo switch. The value should be greater than 99%. If not then increase the redo log file size or use faster disks for redo log files.

Run the hitratio script to get the ratios.

Thanks