The ‘iostat’ command does not show VxVM devices
Article ID: 100054599
Updated On:
Description
Error Message
There is no error message. The VxVM devices simply do not appear in the ‘iostat’ output.
Cause
VxVM has two IO modes: BIO mode and Request mode.
VxVM does not support the ‘iostat’ command for BIO mode as there will be a significant performance drop for ‘iostat’ in BIO mode..
The following command shows if BIO mode is enabled or disabled.
# vxtune vol_use_rq
Tunable Current Value Default Value Reboot Clusterwide
------------------------------- ------------- ------------- ------ -----------
vol_use_rq 0 2 Y N
If the current value of vol_use_rq is ‘0’, then BIO mode is enabled. Otherwise Request mode is enabled.
Resolution
In order to analyze IO statistics for VxVM devices when BIO mode is enabled, use ‘vxstat’ instead of 'iostat'.
Issue/Introduction
Error Message
There is no error message. The VxVM devices simply do not appear in the ‘iostat’ output.Additional Information
