Database Reference
In-Depth Information
dynamic view. This result will help you adjust the AMS POWER LIMIT values to rebalancing operation. The following
demonstration explains how to do that:
EXPLAIN WORK FOR ALTER DISKGROUP dg_data REPLACE disk dg_data_004 WITH '<new_asm_disk>' POWER 3;
SQL> SELECT est_work FROM V$ASM_ESTIMATE;
Based on the result you get, you can increase or decrease the power limit of the disk rebalancing operation.
What-If Command Evaluation
Clusterware administrators often need to perform certain cluster management operations on the cluster
environment. It has been a challenge to evaluate potential impact of these operations on the production of the cluster
and RAC environment prior to these operations. Oracle Clusterware 12c provides a new feature called the What-if
command Evaluation for this kind of purpose. This feature allows us to determine the impact of certain operations
without actually executing these commands to the cluster. And of course, since the command has not actually been
executed, the actual impact doesn't actually occur.
The What-if command Evaluation consists of a set of evaluation commands and what-if API to preview a cluster
management operation. We can use these commands to analyze and determine the impact of a certain operation
before actually executing the operation. As a result, this feature allows you to simulate the command and review
potential results without actually making the changes on the system.
You can perform What-if command Evaluation application resources with CRSCTL using the eval option:
$crsctl eval {start | stop | relocate | modify | add | fail| resource
You can perform What-if command Evaluation on Oracle Clusterware resource:
$ crsctl eval {add | delete | modify | serverpool
$ crsctl eval {add | delete | relocate| delete server
$ crsctl eval active policy
Here is an example that shows the potential impact of deleting server knewrac4 from the cluster:
$ crsctl eval delete server knewracn4
Stage Group 1:
---------------------------------------------------------------------------------------------------
--------
Stage Number Required Action
---------------------------------------------------------------------------------------------------
--------
1 Y Server 'knewracn4' will be removed from pools
[ora.knewspool]
Y Resource 'ora.ASMNET1LSNR_ASM.lsnr' (knewracn4)
will be in state [OFFLINE]
Y Resource 'ora.DATA1.dg' (knewracn4) will be in
state [OFFLINE]
Y Resource 'ora.LISTENER.lsnr' (knewracn4) will be
in state [OFFLINE]
