On Fri, Nov 7, 2008 at 6:55 PM, Finn Jorgensen <finn.oracledba@xxxxxxxxx> wrote: > Because of the way ASM distributes data evenly across all disks in a > diskgroup, adding 200GB disks to an existing diskgroup comprising of 50GB > disks means you will never be able to use more than 50GB of those 200GB > disks. I agree with this... > You will have to add those disks to a separate diskgroup and then start > moving data over, which means downtime. but could you not add(2x200)/rebalance, drop(6x50GB)/rebalance to get all the data onto the 2x200GB? this would alleviate downtime but... I would never put my whole database only on 2 spindles anyway. If I recall correctly, if there is not room to mirror ASM extents from the failed drive, the diskgroup will dismount to protect from catastrophic failure. This means in a two disk ASM group, losing one disk will result in a down database. There there is also a special case with 3 disks, as each is in their own failgroup and I believe the usable space (for files) for 3 disks is the same as 2 disks (or something similar). So basically the minimum recommended disks is four. It comes back to disk space is cheap... -- Regards, Greg Rahn http://structureddata.org -- //www.freelists.org/webpage/oracle-l