3 Replies Latest reply on Oct 18, 2013 7:35 AM by JohnWatson

    Can ASMLib and udev disks co-exist


      Grid version:

      OS : RHEL 5.8



      Currently we use ASMLib to stamp our LUNs. We want to start using udev for the device persistancy in our RAC Nodes.

      Can disks labelled using ASMLib and disks named by udev co-exist in a single disk group ?

        • 1. Re: Can ASMLib and udev disks co-exist

          If /ect/init.d/oracleasm listdisk command lists the disk named by udev , than you can put them in single diskgroup.




          • 2. Re: Can ASMLib and udev disks co-exist

            What do you mean by "stamp the LUN"?


            If it means writing a disk label - ASMLib is not needed for that as ASM itself writes the disk label/header to disk (upon doing commands like create diskgroup).


            If it means creating a logical device/symbolic link to a LUN - then no, ASMLib can no longer be used for this as udev/multipath will create the required devices and logical devices.


            ASM itself does not care what the o/s calls the device. It does not use that name to identify anything. A disk is always opened and the header read, in order to determine if that disk is an existing or former diskgroup member, or an available disk (one without an ASM disk label).


            This means that you should be able to rip out ASMlib, use multipath instead, and simply change the ASM disk discovery string to /dev/mpath, in order for ASM to mount its diskgroups.

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            • 3. Re: Can ASMLib and udev disks co-exist

              I don't see why you can't mix udev and ASMlib defined devices, just set your asm_diskstring accordingly. In this example, I'm mixing ASMlib and NFS devices and it works no problem:



              SQL> sho parameter asm_d


              NAME                                 TYPE        VALUE

              ------------------------------------ ----------- ------------------------------

              asm_diskgroups                       string      ACFSV1, ACFSV2

              asm_diskstring                       string      ORCL:*, /u01/nfs_shares/asm/ir


              SQL> select path from v$asm_disk;





















              16 rows selected.