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8 Replies Latest reply: Jan 11, 2013 10:37 PM by Dude! RSS

Add luns in asm instance...

oradba11 Newbie
Currently Being Moderated
Hi,
I need to configure Oracle ASM to include 5 additional new LUN . The oracle database is already up and running on an Oracle DB. The DB is already configured for 6 LUNs, but we need the DB updated to include the 5 new LUNs.

Already Configured disks:

/dev/rhdisk1 - 100 GB
/dev/rhdisk2 - 100 GB
/dev/rhdisk3 - 100 GB
/dev/rhdisk4 - 100 GB
/dev/rhdisk5 - 100 GB
/dev/rhdisk6 - 30 GB

New Disks to Configure:

/dev/rhdisk7
/dev/rhdisk8
/dev/rhdisk9sy
/dev/rhdisk10
/dev/rhdisk11

Please let me know steps how to do it and what all informance i need to do it..
  • 1. Re: Add luns in asm instance...
    KuljeetPalSingh Guru
    Currently Being Moderated
    add the new disk into existing diskgroup by alter diskgroup add disk cmd...


    http://docs.oracle.com/cd/B28359_01/server.111/b31107/asmdiskgrps.htm#CHDBIFGA

    also check redundancy level of ASM diskgroup and add disk accordingly.
  • 2. Re: Add luns in asm instance...
    oradba11 Newbie
    Currently Being Moderated
    Is that adding disks to existing diskgroups ...is same is adding luns ...?

    how to find which disk to add in which disk group ..?
  • 3. Re: Add luns in asm instance...
    KuljeetPalSingh Guru
    Currently Being Moderated
    candidate disk can be added into any existing disk group.

    for this you can check the header_status in v$asm_disk to CANDIDATE
    http://docs.oracle.com/cd/B28359_01/server.111/b28320/dynviews_1020.htm
  • 4. Re: Add luns in asm instance...
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    oradba11 wrote:

    I need to configure Oracle ASM to include 5 additional new LUN .
    Not necessary. ASM either sees these LUNs. Or not. There is no ASM side configuration needed to use/see these additional LUNs or make them visible.
    The oracle database is already up and running on an Oracle DB. The DB is already configured for 6 LUNs, but we need the DB updated to include the 5 new LUNs.

    Already Configured disks:
    /dev/rhdisk1 - 100 GB
    ..snipped..
    New Disks to Configure:
    /dev/rhdisk7
    ..snipped..
    Which means the ASM disk discovery string should be "+/dev/rdisk*+". And implies that ASM will automatically see these LUNs when made available by the o/s.

    No additional steps needed on the ASM side.

    On the o/s side, the new devices need to have the proper permissions in order for ASM to see and use these devices. So permissions need to be set in order for ASM to see these new devices. Assuming that is done, ASM will see these new LUNs.. just as it sees the existing LUNs. (ASM does not know the difference until it checks the header of each LUN to determine whether it is a member disk, or a candidate disk).
  • 5. Re: Add luns in asm instance...
    Dude! Guru
    Currently Being Moderated
    Based on your device name I assume you are using AIX?

    Perhaps you can implement the following, which will give you more control as to what disks to make available for ASM.

    Get the major and minor number using ls -l /dev/hdisk7. E.g. 1 2
    Create a directory named /dev/asm
    Create a special character device name, e.g. asmdisk_1
    mknod /dev/asm/asmdisk_1 c 1 2
    Add the right ownership
    chmod oracle:dba /dev/asm/asmdisk_1

    Configure the asm_diskstring of your ASM instance to /dev/asm/*
    E.g.: alter system set asm_diskstring='/dev/asm/*';
  • 6. Re: Add luns in asm instance...
    onedbguru Pro
    Currently Being Moderated
    oradba11 wrote:
    Hi,
    I need to configure Oracle ASM to include 5 additional new LUN . The oracle database is already up and running on an Oracle DB. The DB is already configured for 6 LUNs, but we need the DB updated to include the 5 new LUNs.

    Already Configured disks:

    /dev/rhdisk1 - 100 GB
    /dev/rhdisk2 - 100 GB
    /dev/rhdisk3 - 100 GB
    /dev/rhdisk4 - 100 GB
    /dev/rhdisk5 - 100 GB
    /dev/rhdisk6 - 30 GB
    Is rhdisk6 in the same diskgroup as 1-5?? if so, you are going to have major problems. ALL LUNS IN A DISKGROUP MUST BE THE SAME SIZE.

    select group#, member from v$asm_diskgroup order by group#;

    If disk 6 is in the same diskgroup, you must take steps to make it the same size.
    Steps to do this:
    add new 100G device - let it rebalance
    remove disk6
    resize disk6 to 100G
    add disk6 back to the diskgroup.

    New Disks to Configure:

    /dev/rhdisk7
    /dev/rhdisk8
    /dev/rhdisk9sy
    /dev/rhdisk10
    /dev/rhdisk11

    Please let me know steps how to do it and what all informance i need to do it..
    Make sure the new devices are the same size as well!!!!
  • 7. Re: Add luns in asm instance...
    TSharma-Oracle Guru
    Currently Being Moderated
    alter diskgroup 'diskgroup_name' add disk '/dev/rhdisk7'
  • 8. Re: Add luns in asm instance...
    Dude! Guru
    Currently Being Moderated
    ... ALL LUNS IN A DISKGROUP MUST BE THE SAME SIZE.
    not necessarily, but it is recommended for balanced I/O and optimal performance that disks in a given disk group have similar size and performance characteristics.

    http://docs.oracle.com/cd/E11882_01/server.112/e18951/asmprepare.htm

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