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2 Replies Latest reply: May 22, 2013 6:04 AM by Kavanagh RSS

zero padding the LUN using dd command in Linux

Kavanagh Newbie
Currently Being Moderated
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 Expert
    Currently Being Moderated
    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 Newbie
    Currently Being Moderated
    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 ?

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