Alejandro Vargas' Blog

Manually changing rebalance power on an ongoing ASM rebalance operation

Alejandro Vargas
Technical Leader, ACS Global Delivery, Infrastructure & BigData

A couple of times I've removed ASM disks from a diskgroup and found that the rebalance operation will take too long.

This is not a problem when you don't want to disturb online users, the rebalance process only locks for writes 1mb of data at a time, so letting the rebalance to run slowly has no performance impact.

My problem was that I needed to free the disks as fast as possible in order to finish some IO tests within a limited timeframe.

The procedure to change the rebalance power of an ongoing operation is very simple:

alter diskgroup DATADG rebalance power 6;

After that the rebalance operation will restart with the new set rebalance power.

For a complete example check this document:

Changing the rebalance power of an ongoing rebalance operation

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Comments ( 1 )
  • Oracle Certification Friday, July 11, 2008
    Thanks for the tip. Didn't know you could remove the asm disk without disturbing other users. Takes ages otherwise.
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