Estimate the amount of work for a rebalance operation

You can estimate the amount of work with v$ASM_ESTIMATE view. EST_WORK column provides an estimate of the number of allocation units that have to be moved by the rebalance operation to complete.

Note: Est_work column provide the information of allocation unit that is moved during rebalance operations.

Example of estimating the drop disk command

-- Estimate the drop disk work
EXPLAIN WORK FOR ALTER DISKGROUP diskgroup2 DROP DISK diska1;

--Check the view for estimate:
SELECT est_work FROM V$ASM_ESTIMATE;
EST_WORK
--------
5600


Example of estimating the disk online for a diskgroup

--Estimate of online the disk in a diskgroup using statement id
EXPLAIN WORK SET STATEMENT_ID='online' FOR ALTER DISKGROUP diskgroup2
ONLINE disk diska1;

--Check the view for estimate:
SELECT est_work FROM V$ASM_ESTIMATE WHERE STATEMENT_ID='online';
EST_WORK
--------
200


Please refer for rebalance operation commands in Oracle ASM: Rebalance operation in Diskgroup Oracle ASM