7 Replies Latest reply: May 22, 2011 3:06 PM by Levi Pereira RSS

    what is the correct procedure to drop asm diskgroup is rac?

    863526
      Hi,

      I would like to drop a asm diskgroup in RAC? what is the correct procedure?
      1.do I have to unmount the diskgroup first in the 2 nodes?
      2. alter diskgroup xxx drop command to be run in the 2 nodes or just 1 node?
      3. after droping command, is there any other procdures to do?

      any doc to follow?

      thanks

      andrew
        • 1. Re: what is the correct procedure to drop asm diskgroup is rac?
          Levi Pereira
          Hi,

          What's version of ASM?
          860523 wrote:
          I would like to drop a asm diskgroup in RAC? what is the correct procedure?
          1.do I have to unmount the diskgroup first in the 2 nodes?
          If you are using ASM 11.2, I recommend you use the utility ASMCA to drop DISKGROUP.

          If you are using ASM 11.1 or earlier use SQLPLUS.
          Dismount Diskgroup from all the ASM instances, except from one.
          Drop diskgroup from the ASM instance, which the diskgroup is still mounted
          Just it.

          If you query v$asm_disk the header_status must be "FORMER" on asmdisks that belonged to the diskgroup dropped.
          FORMER - Disk was once part of a disk group but has been dropped cleanly from the group.
          2. alter diskgroup xxx drop command to be run in the 2 nodes or just 1 node?
          Execute command only one ASM instance
          3. after droping command, is there any other procdures to do?
          No.
          any doc to follow?
          How To Add a New Disk(s) to An Existing Diskgroup on RAC (Best Practices). [ID 557348.1]

          Regards,
          Levi Pereira
          • 2. Re: what is the correct procedure to drop asm diskgroup is rac?
            863526
            Hi Levi,

            thank you very much. oracle 10.2, if I unmount the diskgroup, do I have to offline something or what is the procedure before alter disgroup xxx unmount?

            thanks again

            andrew
            • 3. Re: what is the correct procedure to drop asm diskgroup is rac?
              Levi Pereira
              Hi Andrew,
              860523 wrote:
              thank you very much. oracle 10.2, if I unmount the diskgroup, do I have to offline something or what is the procedure before alter disgroup xxx unmount?
              You MUST remove (using DBCA) or move (using RMAN) all database stored on this diskgroup (if exists) before dropping DISKGROUP.
              1) Check if exists database using this DISKGROUP.
              The query above must return no rows.
              SQL>  SELECT D.NAME,C.INSTANCE_NAME,C.DB_NAME,C.STATUS
                   FROM GV$ASM_DISKGROUP D , GV$ASM_CLIENT C
                   WHERE D.GROUP_NUMBER=C.GROUP_NUMBER
                   AND D.NAME = '<DISKGROUP_NAME>';  
              
              no rows selected
              If query above return rows you must shutdown all instance first and remove or move database to another DISKGROUP.

              2) Dismount Diskgroup from all the ASM instances, except from one.
              ALTER DISKGROUP <DISKGROUP_NAME> DISMOUNT;
              3)Drop diskgroup from the ASM instance, which the diskgroup is still mounted
              DROP DISKGROUP <DISKGROUP_NAME>; -- If no files on DISKGROUP
              DROP DISKGROUP <DISKGROUP_NAME> INCLUDING CONTENTS; - If exits files on DISKGROUP
              Just it.

              Regards,
              Levi Pereira
              • 4. Re: what is the correct procedure to drop asm diskgroup is rac?
                863526
                thanks Levi, I've already marked the answer as correct. However, another question, sorry, I have no testing rac environment to test. We've only got production rac .

                - if I unmount diskgroup on node1 and then after serveral hours I dismount this diskgroup in node 2 - just to make sure no errors and nothing is pointed to this diskgroup.
                - will there be error if I mount this diskgroup back to node 2 before I can drop it, (may be not in sync since the diskgroup is dismounted from 2 nodes at different times)?

                thanks

                andrew
                • 5. Re: what is the correct procedure to drop asm diskgroup is rac?
                  Levi Pereira
                  Hi Andrew,
                  860523 wrote:
                  - if I unmount diskgroup on node1 and then after serveral hours I dismount this diskgroup in node 2 - just to make sure no errors and nothing is pointed to this diskgroup.
                  I recommend you first of all check files on DISKGROUP. Indentify if this files is used by any databases. So I recommended you delete or move database (i.e: all files) before dropping Diskgroup. If no files on DISKGROUP then none databases use this DISKGROUP.

                  You can use the query below to identifiy this files.

                  e.g:
                  set linesize 200
                  col FULL_ALIAS_PATH for A70
                  select concat('+'||gname, sys_connect_by_path(aname, '/')) full_alias_path, 
                         system_created, alias_directory, file_type
                       from ( select b.name gname, a.parent_index pindex, a.name aname, 
                                a.reference_index rindex , a.system_created, a.alias_directory,
                                c.type file_type
                         from v$asm_alias a, v$asm_diskgroup b, v$asm_file c
                         where a.group_number = b.group_number
                               and a.group_number = c.group_number(+)
                               and a.file_number = c.file_number(+)
                               and a.file_incarnation = c.incarnation(+)
                       ) 
                  start with (mod(pindex, power(2, 24))) = 0
                              and rindex in 
                                  ( select a.reference_index
                                    from v$asm_alias a, v$asm_diskgroup b
                                    where a.group_number = b.group_number
                                          and (mod(a.parent_index, power(2, 24))) = 0
                                          and b.name = UPPER('&DG_NAME')
                                  )
                  connect by prior rindex = pindex;
                  - will there be error if I mount this diskgroup back to node 2 before I can drop it, (may be not in sync since the diskgroup is dismounted from 2 nodes at different times)?
                  Does not matter which time or order that diskgroup was dismounted. It's mandatory the diskgroup be mounted in only one Instance before DROP.

                  Regards,
                  Levi Pereira
                  • 6. Re: what is the correct procedure to drop asm diskgroup is rac?
                    863526
                    Hi Levi,

                    since the diskgroup contains FRA, there is no datafile. so I just want to make sure.
                    If I dismount disks on 2 nodes are different times, will I be able to mount it back without error?

                    thanks very much again

                    andrew
                    • 7. Re: what is the correct procedure to drop asm diskgroup is rac?
                      Levi Pereira
                      Hi,
                      860523 wrote:
                      Hi Levi,

                      since the diskgroup contains FRA, there is no datafile. so I just want to make sure.
                      If I dismount disks on 2 nodes are different times, will I be able to mount it back without error?
                      Of course yes.

                      The same happens when you shutdown one node (or both). You can mount without problem.

                      Levi Pereira