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3 Replies Latest reply: Jul 30, 2013 4:31 PM by Levi-Pereira RSS

ASM re-install

william lara Newbie
Currently Being Moderated

Hi,

 

We did a fresh installation of ASM on RHEL 6.4.  This a stand Grid Infrastructure for a Standalone Server.

 

The install ran cleanly.  We created one disk group called DATA of 5 100GB drives and one disk group called FLASH of 2 100GB drives.  We chose the default au_size of 1MB.

 

After reviewing some notes on this forum AU size criteria with Oracle 11gR2 we decided to modify the au_size of DATA and FLASH.

 

We were able to dismount and drop FLASH but not DATA since DATA was in use (I guess by the grid infrastructure).

 

We decided to go ahead and uninstall since we had no database on the grid infrastructure yet.  This a fresh install and we saw no other method to modify the au_size of the original disk group (DATA).

 

We had to do $GRID_HOME/bin/rootcrs.pl -deconfig -force  (as root while the grid infrastructure was running I think)

 

Then we ran $GRID_HOME/deinstall/deinstall as grid.

 

Finally we removed the residule files left behind as root to complete this uninstall.

 

When we attmempted to reinstall grid the drives are showing up as Status "Member" so we are unable to re-install at this point.

 

Should we use dd to clear off the headers for the ASM drives?  # dd if=/dev/zero of=/dev/oracleasm/asm01 bs=1024 count=100

So that we can reuse the drives....

 

Any advise on re-installing in a better way in the future?

 

Many thanks in advance,

William

  • 1. Re: ASM re-install
    Levi-Pereira Guru
    Currently Being Moderated

    Hi,

     

    We were able to dismount and drop FLASH but not DATA since DATA was in use (I guess by the grid infrastructure).

    We decided to go ahead and uninstall since we had no database on the grid infrastructure yet.  This a fresh install and we saw no other method to modify the au_size of the original disk group (DATA).

     

    First of all, you don't need reinstall Oracle GI to change AU_SIZE. You need only recreate that Diskgroup.

     

    Options to change AU_SIZE:

    1. Create a New Diskgroup with desired AU_SIZE and move data from one DISKGROUP to another.

    2. Backup all data from DISKGROUP to filesystem or other DISKGROUP, drop DISKGROUP, create it with desired  AU_SIZE, restore all data.

     

    Diskgroup DATA unable to dismount. It's due ASM SPFILE was stored on diskgroup DATA.

    The option to solve was simple. Move SPFILE to a local filesystem restart ASM and you will manage dismount/recreate DISKGROUP DATA.

     

    Using:

    $ asmcmd spbackup

    $ asmcmd spcopy

    $ asmcmd spget

    $ asmcmd spset

     

    To avoid DISKGROUP get stucked by ASM SPFILE, in all Oracle GI Standalone Installation I always create a small Diskgroup (+ASM_SPFILE) size 100M  using a local diskpartition or a lun of storage to store ASM SPFILE during installation.

    It's will help you in future maintenance on its diskgroups which store databases, such as dismount/mount/drop/recreate

     

    Should we use dd to clear off the headers for the ASM drives?  # dd if=/dev/zero of=/dev/oracleasm/asm01 bs=1024 count=100

    So that we can reuse the drives....

     

    No, You can use ASMCA to create a DISKGROUP by using  FORCE option on that LUN, it will destroy old disk header by replacing to new DISKGROUP.


    Any advise on re-installing in a better way in the future?

    Yes, You don't need reinstall just perform maintenance task on its diskgroup.

     

    Regards,

    Levi Pereira

    http://levipereira.wordpress.com/

  • 2. Re: ASM re-install
    william lara Newbie
    Currently Being Moderated

    Hi Levi,

     

    Thank you for you advise.

     

    Since I have already uninstalled on this test system as I mention.  You recommend taking an additional small drive 100MB using that for my next install.  Let's call it CORE for the +ASM_SPFILE

     

    Then using ASMCA I can use the FORCE option to redefine my old drives.

     

    Sound about right?

     

    Thanks,

    William

  • 3. Re: ASM re-install
    Levi-Pereira Guru
    Currently Being Moderated

    Hi Willian,

     

    Placing ASM SPFILE on DISKGROUP is a option, ASM SPFILE is a file with few Kbytes which you can store under GI_HOME/dbs.

     

    During the creation of ASM Instance, ASMCA store ASM SPFILE on first DISKGROUP created, so because that I always create a small diskgroup at moment creation of ASM Instance to store this file which will prevent maintenance on that diskgroup.

    We can easily in the future we change the location of the ASM SPFILE, so is not mandatory create a diskgroup only for it.

     

    Then using ASMCA I can use the FORCE option to redefine my old drives.

    Yes, Some DBA  like to use DD command that is quite dangerous, making obsolete the use of FORCE option.

    FORCE option doesn't change a ASMDISK in use, DD command does.

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