If the Server Has High Redundancy

When the server has high redundancy disk groups, so that Oracle ASM has multiple mirror copies for all the grid disks of the failed server, then take the failed cell offline. After Oracle ASM times out, it automatically drops the grid disks on the failed server, and starts rebalancing the data using mirror copies.

The default time out is two hours. If the server rescue takes more than two hours, then you must re-create the grid disks on the rescued cells in Oracle ASM.