5 Replies Latest reply on Jan 7, 2013 8:19 AM by CoBy

    Shared storage for 11gR2 RAC

      Dear all

      I've asked sysadmins to provide me shared storage for two node rac. Theye've provided those storages.

      - I've formated it using /sbin/fdisk on both nodes. Is it correct to format it on both nodes or one node is enough?

      Should I use asmlib to make those devices to be appeared during ASM installation? Or should I install any cluster file system on those devices? The shared storage is for Dell

        • 1. Re: Shared storage for 11gR2 RAC
          as disks are shared you just need to partition on one node.Once partition is done, just mark the disks as ASM disks using the asmlib on one node only, on other nodes just scan the disks.
          /etc/init.d/oracleasm config   --> it will asks for who needs to be owned these disks.
          /etc/init.d/oracleasm createdisk <diskname> <diskpath/name>  ---> create on one node
          --on remaining nodes use scan
          /etc/init.d/oracleasm scandisks 
          --finally run following on all nodes and make sure disks are available
          /etc/init.d/oracleasm listdisks  
          • 2. Re: Shared storage for 11gR2 RAC
            Hi Friend,

            Oracle recommends for RAC :

            1. Use ASMLib for ease of management and for increased performance provided by the ASMLib Async I/O driver.
            2. When using ASMLib in a multipath environment ensure that ASMLib has been configured properly such that the multipath device is used for access to the devices.
            3. OCFS2 on a RAC system since it adds additional complexity to the cluster. Use of ASM is the current and future direction for storage on a RAC system and is a highly recommended best practice.
            4. OCFS2 1.2.7-1 can make the OCFS2 filesystem(s) become unavailable for access after a node panic or a node eviction occurs. Users are advised to upgrade to OCFS2 1.2.8-2 as soon as possible.

            Hope it helps....

            • 3. Re: Shared storage for 11gR2 RAC
              IMprofessionalO ASMLib is superfluous to ASM. After installing and configuring > 75 clusters (upwards of 150 nodes) and never using it except to test it once and finding it useless.

              If you properly configure udev/multipath, ASM will function very well.
              • 4. Re: Shared storage for 11gR2 RAC
                Hi and thank you all for your answers
                Could you tell me how to configure udev multipath?

                thanks in advance
                • 5. Re: Shared storage for 11gR2 RAC

                  I am also about to try this approach without asmlib. I found this : http://oramurali.files.wordpress.com/2012/03/usingudevrh.pdf
                  It is a bit old, but it should generally work. Once I complete the installation on OEL 6.3 I will update the information.

                  best regards,