Collecting I/O statistics


Collecting I/O statistics
Prev	Determining candidates for Cached Quick I/O	Next

Once you have enabled Cached Quick I/O on a file system, you need to collect statistics to determine and designate the files that can best take advantage of its benefits.

To collect statistics needed to determine files that benefit from Cached Quick I/O

Reset the qiostat counters by entering:

$ /opt/VRTS/bin/qiostat -r /mount_point/filenames

Run the database under full normal load and through a complete cycle (24 to 48 hours in most cases) to determine your system I/O patterns and database traffic in different usage categories (for example, OLTP, reports, and backups) at different times of the day.
While the database is running, run qiostat -l to report the caching statistics as follows:
```
$ /opt/VRTS/bin/qiostat -l /mount_point/filenames
```
or, use the -i option to see statistic reports at specified intervals:
```
$ /opt/VRTS/bin/qiostat -i n /mount_point/filenames
```
where n is time in seconds

For example:

To collect I/O statistics from all database containers on file system /db01:
```
    $ /opt/VRTS/bin/qiostat -l /db01/*
```