Unable to get the diskgroup mounted or dropped.
Main issue is that need to get this diskgroup dropped so can use the disks in another diskgroup.
Dropping a diskgroup requires that it be mounted. If the diskgroup cannot be mounted then you need to overwrite the first block of the disk to make it not look like a disk in the diskgroup you want to drop. There are several ways to accomplish this. All of them are dangerous because you can destroy a working diskgroup if you type in the wrong device name for the disk
1. You can use 'dd' Unix command to write a block of zero on the disk header in block 0.
2. You can just add the disk to a new diskgroup using the FORCE option.
3. You can create a new diskgroup using all the disks in the old diskgroup with the FORCE option. The new diskgroup can then be mounted and dropped. The only advantage of this over choice 2 is that the FORCE adds are all done at once so the adds to new diskgroups can be done over time with out making a habit of using FORCE.
The following steps would be one way to accomplish this.
1. Create a new diskgroup FORCE'ing disks over to new diskgroup. Once disks are forced over to new diskgroup, the original diskgroup (CIF_RECO_01 in this example) no longer exists.
Note: The previous statement is a destructive operation, since the ‘FORCE’ option will clear any former ASM metadata and initialize the disks with the new ASM metadata associated with the new diskgroup in question, therefore all the former data structures allocated in associated disks (specified in the CREATE DISKGROUP statement) will be wipe out. For this reason, if you are not sure about the listed disks, then please open a Service Request (SR) with Oracle Support and we will be glad to assist you with this task.
2. Verify mounted.
3. Drop the new diskgroup to free up the disks.
4. Verify disks header
The header_status for the disks should be FORMER, which indicates the disk was once part of a disk group, and it may be added to a new disk group with the ALTER DISKGROUP statement
5. Then add the disks to CIF_DATA_02, the intended diskgroup.
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