Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

capable of adopting reasonable defaults for all configuration parameters. On very
large systems, however, there may be configurations that require additional tuning
of these parameters, both for capacity and performance reasons.
For more information on tuning VxVM, see the Veritas Volume Manager
Administrator's Guide.
About obtaining volume I/O statistics
If your database is created on a single file system that is on a single volume, there
is typically no need to monitor the volume I/O statistics. If your database is created
on multiple file systems on multiple volumes, or the volume configurations have
changed over time, it may be necessary to monitor the volume I/O statistics for
the databases.
Use the vxstat command to access information about activity on volumes, plexes,
subdisks, and disks under VxVM control, and to print summary statistics to the
standard output. These statistics represent VxVM activity from the time the
system initially booted or from the last time the counters were reset to zero. If no
VxVM object name is specified, statistics from all volumes in the configuration
database are reported. Use the -g option to specify the database disk group to
report statistics for objects in that database disk group.
VxVM records the following I/O statistics:
■ count of operations
■ number of blocks transferred (one operation can involve more than one block)
■ average operation time (which reflects the total time through the VxVM
interface and is not suitable for comparison against other statistics programs)
VxVM records the preceding three pieces of information for logical I/Os, including
reads, writes, atomic copies, verified reads, verified writes, plex reads, and plex
writes for each volume. VxVM also maintains other statistical data such as read
failures, write failures, corrected read failures, corrected write failures, and so
on. In addition to displaying volume statistics, the vxstat command is capable of
displaying more detailed statistics on the components that form the volume. For
detailed information on available options, refer to the vxstat(1M) manual page.
To reset the statistics information to zero, use the -r option. You can reset the
statistics information for all objects or for only those objects that are specified.
Resetting just prior to an operation makes it possible to measure the impact of
that particular operation.
The following is an example of output produced using the vxstat command:
OPERATIONS BLOCKS AVG TIME(ms)
Tuning for performance
About tuning VxVM
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