Good after noon everyone. Today I wanna share you how you can increase rebalance speed for ADVM volume if you didn’t know it yet. Since 11g Oracle has new feature by the name “ASM Fast Rebalance”. All you need to achieve this feature is remount your diskgroup which contain ADVM volume in the restricted mode.
SQL>; alter diskgroup data dismount force; Diskgroup altered. SQL>; alter diskgroup data mount restricted; Diskgroup altered.
This restricted mode prevent any connection from RDBMS and cluster agents for ADVM. And it’s eliminate locks extent map during rebalance operations. In my environment with diskgroup which contain 15Tb ADVM volume, rebalance operation in the normal mount state has took 15 hours for ADVM volume plus 5 hours for database files, and 20 hours in total. When I’ve re-mounted diskgroup in the restricted mode rebalance operation has took 4 hours for ADVM volume plus 3 hours for database files, and 7 hours in total. So as you can see ASM Fast Rebalance has increased my rebalance operations in 3 times.