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Performance monitoring and tuning

Tuning VxVM

To set the number of configuration copies for a new disk group, use the nconfig operand with the vxdg init command (see the vxdg(1M) manual page for details).

You can also change the number of copies for an existing group by using the vxedit set command (see the vxedit(1M) manual page). For example, to configure five configuration copies for the disk group, bigdg, use the following command:

#vxedit set nconfig=5 bigdg

Changing the values of tunables

Tunables are modified by using the System Management Homepage (SMH) or the kctune utility. Changed tunables take effect only after relinking the kernel and booting the system from the new kernel.

The values of system tunables can be examined or changed in SMH by selecting Home > System Configuration > Kernel Configuration > Tunables.

Most DMP tunables may be set online (without requiring a reboot) by using the vxdmpadm command as shown here:

#vxdmpadm settune dmp_tunable=value

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 139 for details.

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HP Veritas Volume Manager 5.0 -UX 11i v3 manual Changing the values of tunables, # vxedit set nconfig=5 bigdg