8 Replies Latest reply: Jan 12, 2013 12:37 AM by Catch_22 RSS

    Add luns in asm instance...

    oradba11
      Hi,
      I need to configure Oracle ASM to include 5 additional new LUN . The oracle database is already up and running on an Oracle DB. The DB is already configured for 6 LUNs, but we need the DB updated to include the 5 new LUNs.

      Already Configured disks:

      /dev/rhdisk1 - 100 GB
      /dev/rhdisk2 - 100 GB
      /dev/rhdisk3 - 100 GB
      /dev/rhdisk4 - 100 GB
      /dev/rhdisk5 - 100 GB
      /dev/rhdisk6 - 30 GB

      New Disks to Configure:

      /dev/rhdisk7
      /dev/rhdisk8
      /dev/rhdisk9sy
      /dev/rhdisk10
      /dev/rhdisk11

      Please let me know steps how to do it and what all informance i need to do it..
        • 1. Re: Add luns in asm instance...
          415289
          add the new disk into existing diskgroup by alter diskgroup add disk cmd...


          http://docs.oracle.com/cd/B28359_01/server.111/b31107/asmdiskgrps.htm#CHDBIFGA

          also check redundancy level of ASM diskgroup and add disk accordingly.
          • 2. Re: Add luns in asm instance...
            oradba11
            Is that adding disks to existing diskgroups ...is same is adding luns ...?

            how to find which disk to add in which disk group ..?
            • 3. Re: Add luns in asm instance...
              415289
              candidate disk can be added into any existing disk group.

              for this you can check the header_status in v$asm_disk to CANDIDATE
              http://docs.oracle.com/cd/B28359_01/server.111/b28320/dynviews_1020.htm
              • 4. Re: Add luns in asm instance...
                Billy~Verreynne
                oradba11 wrote:

                I need to configure Oracle ASM to include 5 additional new LUN .
                Not necessary. ASM either sees these LUNs. Or not. There is no ASM side configuration needed to use/see these additional LUNs or make them visible.
                The oracle database is already up and running on an Oracle DB. The DB is already configured for 6 LUNs, but we need the DB updated to include the 5 new LUNs.

                Already Configured disks:
                /dev/rhdisk1 - 100 GB
                ..snipped..
                New Disks to Configure:
                /dev/rhdisk7
                ..snipped..
                Which means the ASM disk discovery string should be "+/dev/rdisk*+". And implies that ASM will automatically see these LUNs when made available by the o/s.

                No additional steps needed on the ASM side.

                On the o/s side, the new devices need to have the proper permissions in order for ASM to see and use these devices. So permissions need to be set in order for ASM to see these new devices. Assuming that is done, ASM will see these new LUNs.. just as it sees the existing LUNs. (ASM does not know the difference until it checks the header of each LUN to determine whether it is a member disk, or a candidate disk).
                • 5. Re: Add luns in asm instance...
                  Catch_22
                  Based on your device name I assume you are using AIX?

                  Perhaps you can implement the following, which will give you more control as to what disks to make available for ASM.

                  Get the major and minor number using ls -l /dev/hdisk7. E.g. 1 2
                  Create a directory named /dev/asm
                  Create a special character device name, e.g. asmdisk_1
                  mknod /dev/asm/asmdisk_1 c 1 2
                  Add the right ownership
                  chmod oracle:dba /dev/asm/asmdisk_1

                  Configure the asm_diskstring of your ASM instance to /dev/asm/*
                  E.g.: alter system set asm_diskstring='/dev/asm/*';
                  • 6. Re: Add luns in asm instance...
                    onedbguru
                    oradba11 wrote:
                    Hi,
                    I need to configure Oracle ASM to include 5 additional new LUN . The oracle database is already up and running on an Oracle DB. The DB is already configured for 6 LUNs, but we need the DB updated to include the 5 new LUNs.

                    Already Configured disks:

                    /dev/rhdisk1 - 100 GB
                    /dev/rhdisk2 - 100 GB
                    /dev/rhdisk3 - 100 GB
                    /dev/rhdisk4 - 100 GB
                    /dev/rhdisk5 - 100 GB
                    /dev/rhdisk6 - 30 GB
                    Is rhdisk6 in the same diskgroup as 1-5?? if so, you are going to have major problems. ALL LUNS IN A DISKGROUP MUST BE THE SAME SIZE.

                    select group#, member from v$asm_diskgroup order by group#;

                    If disk 6 is in the same diskgroup, you must take steps to make it the same size.
                    Steps to do this:
                    add new 100G device - let it rebalance
                    remove disk6
                    resize disk6 to 100G
                    add disk6 back to the diskgroup.

                    New Disks to Configure:

                    /dev/rhdisk7
                    /dev/rhdisk8
                    /dev/rhdisk9sy
                    /dev/rhdisk10
                    /dev/rhdisk11

                    Please let me know steps how to do it and what all informance i need to do it..
                    Make sure the new devices are the same size as well!!!!
                    • 7. Re: Add luns in asm instance...
                      TSharma-Oracle
                      alter diskgroup 'diskgroup_name' add disk '/dev/rhdisk7'
                      • 8. Re: Add luns in asm instance...
                        Catch_22
                        ... ALL LUNS IN A DISKGROUP MUST BE THE SAME SIZE.
                        not necessarily, but it is recommended for balanced I/O and optimal performance that disks in a given disk group have similar size and performance characteristics.

                        http://docs.oracle.com/cd/E11882_01/server.112/e18951/asmprepare.htm