To display the current value of a tunable that is being used by VxVM or DMP, use the following commands with the /proc
file system:
# cat < /proc/sys/vxvm/vxio/vol_maxio
# cat < /proc/sys/vxdmp/dmp_enable_restore_daemon
To change the value of a VxVM or DMP tunable, specify the new value using the vxvoltune
and vxdmptune
commands:
# vxvoltune
vxvm_tunable
value
You must then shut down and reboot the system for the change to take effect. The new value persists across system reboots until it is next changed.
For example, the following command sets the value of vol_maxio
to 8192:
vxvoltune
and vxdmptune
utilities modify the tunable values stored in the /etc/vx/vxvm_tunables
and /etc/vx/vxdmp_tunables
files respectively. It is recommended that you use the vxvoltune
and vxdmptune
commands to change the values stored in these files. Do not edit these files directly.
You can use the vxvoltune
and vxdmptune
commands to display the current values of a tunable parameter that is set in the vxvm_tunables
and vxdmp_tunables
files:
DMP tunables can also be set by using the vxdmpadm
command as shown here:
# vxdmpadm settune
dmp_tunable=value
A value that is set in this way overrides that defined in the /etc/vx/vxdmp_tunables
file.
The values of these tunables can be displayed by using this command:
# vxdmpadm gettune
[dmp_tunable]
The vxdmpadm
command also allows you to configure how DMP responds to I/O errors at the level of the paths to individual arrays.
See "Administering DMP using vxdmpadm" on page 150.