Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

Other tools for analysis
While the output of the qiostat command is the primary source of information
to use in deciding whether to enable Cached Quick I/O on specific files, we also
recommend using other tools in conjunction with qiostat. For example,
benchmarking software that measures database throughput is also helpful. If a
benchmark test in which Cached Quick I/O was enabled for a certain set of data
files resulted in improved performance, you can also use those results as the basis
for enabling Cached Quick I/O.
Enabling and disabling Cached Quick I/O for individual
files
After using qiostat or other analysis tools to determine the appropriate files for
Cached Quick I/O, you need to disable Cached Quick I/O for those individual files
that do not benefit from caching using the qioadmin command.
■ Enable Cached Quick I/O for the file system before enabling or
disabling Cached Quick I/O at the individual file level.
Prerequisites
■ You can enable or disable Cached Quick I/O for individual files
while the database is online.
■ You should monitor files regularly using qiostat to ensure that
a file's cache-hit ratio has not changed enough to reconsider
enabling or disabling Cached Quick I/O for the file.
■ Enabling or disabling Cached Quick I/O for an individual file is also
referred to as setting the cache advisory on or off.
■ See the qioadmin (1) manual page.
Usage notes
Setting cache advisories for individual files
You can enable and disable Cached Quick I/O for individual files by changing the
cache advisory settings for those files.
To disable Cached Quick I/O for an individual file
◆
Use the qioadmin command to set the cache advisory to OFF as follows:
$ /opt/VRTS/bin/qioadmin -S filename=OFF /mount_point
For example, to disable Cached Quick I/O for the file /db01/system.dbf, set
the cache advisory to OFF:
$ /opt/VRTS/bin/qioadmin -S system.dbf=OFF /db01
111Using Veritas Cached Quick I/O
Enabling and disabling Cached Quick I/O for individual files