2 Replies Latest reply: May 22, 2013 8:04 AM by Kavanagh RSS

    zero padding the LUN using dd command in Linux

    Kavanagh
      Grid Infrstructure: 11.2.0.3
      OS : Oracle Enterprise Linux 6.3

      When we were installing RAC in solaris, we used to zero pad all LUNs meant for ASM . We used to do like below
      dd if=/dev/zero of=/dev/rdsk/c0t600A0B8008A4CA005ACd0s0 bs=1024k count=2000
      Now we are going to install RAC in Oracle Linux v6 . When I googled Linux related stuff for RAC , I didn't come across documents in which zero padding is done on LUNs meant for ASM Disk groups.

      Question1. Is zero padding using dd necessary in Linux platform ?

      Question2. If dd command has to be run in the LUN, shouldn't that be done before we create the partition table ?
        • 1. Re: zero padding the LUN using dd command in Linux
          Balazs Papp
          Question1. Is zero padding using dd necessary in Linux platform ?
          No, never did that, not even on Solaris.
          Question2. If dd command has to be run in the LUN, shouldn't that be done before we create the partition table ?
          Of course it should.
          What would be the point of creating the partition table and after that overwriting it with 0-s :)


          Do you use a NAS for ASM disks?
          Solaris: http://docs.oracle.com/cd/E11882_01/install.112/e24616/storage.htm#CACDHHJJ
          Linux: http://docs.oracle.com/cd/E11882_01/install.112/e22489/storage.htm#CFACJAGB
          • 2. Re: zero padding the LUN using dd command in Linux
            Kavanagh
            Thank you Balazs

            Do you use a NAS for ASM disks?


            Yes it is NAS. This is going to be a test installation using Openfiler . RAC VMs on VMWare Workstation 9.

            We want to use udev rules file instead of ASMLib. Any extra stuff we need to at Linux level when the LUNs are presented from NAS as opposed to Hitachi/EMC LUNs through FC ?