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3 Replies Latest reply: Dec 6, 2012 11:46 AM by Dude! RSS

RHEL6: udev and ASM

869799 Newbie
Currently Being Moderated
Hi,

As I found out, Oracle does not provide the RPM for asmlib any more for RHEL6.

The alternative is udev: you have to write some rules to get persistent names for your devices, i.e.:

KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id --whitelisted --replace-whitespace --device=/dev/$name",RESULT=="3600c0ff000112a6d0b0ebf5001000000",NAME+="oracleasm/disks/OCR1", OWNER="grid" GROUP="asmadmin" MODE="0660"

After the first tests I have some questions:

* using udev rules with the "NAME+=" option, the device is renamed. For example, /dev/sdc is not available any more if there is a rule that applies for this device. A bit strange, because in /proc/partition it is still listed. Is there a way to have both? The original device (/dev/sdc) and the "newly created" device (for example /dev/oracleasm/disks/OCR1)? I know that you can use SYMLINK but is this supported/recommended?

* is it recommended to use partitions here? If so, udev does not seem to map / rename partitions but devices only...

Any feedback is appreciated,

Werner
  • 1. Re: RHEL6: udev and ASM
    Dude! Guru
    Currently Being Moderated
    If you do not have a RHEL subscription and support, why not using Oracle Linux 6 instead, which is free including updates and provides ASMLib support?

    Regarding udev, perhaps it is best to explain it by an example:

    Get the unique device name:
    # /sbin/scsi_id -g -u -d /dev/sdb
    1ATA_VBOX_HARDDISK_VB77dc9e66-e0db83a8
    Create 2 partitions /dev/sdb1 and /dev/sdb2 using fdisk or parted, e.g.:
    parted -s /dev/sdb mkpart primary 1MB 1000MB
    parted -s /dev/sdb mkpart primary 1000MB 100%
    
    # parted -s /dev/sdb print
    Model: ATA VBOX HARDDISK (scsi)
    Disk /dev/sdb: 8590MB
    Sector size (logical/physical): 512B/512B
    Partition Table: msdos
    
    Number  Start   End     Size    Type     File system  Flags
     1      1049kB  1000MB  999MB   primary
     2      1000MB  8590MB  7590MB  primary
    Create a rule file:
    # vi /etc/udev/rules.d/80-oracleasm.rules
    
    Enter the following data:
    
    KERNEL=="sd?1", BUS=="scsi", PROGRAM=="/sbin/scsi_id -g -u -d /dev/$parent", RESULT=="1ATA_VBOX_HARDDISK_VB77dc9e66-e0db83a8", NAME="ORCLASM1", OWNER="oracle", GROUP="dba", MODE="0660"
    Restart UDEV:
    /sbin/start_udev
    Check the ORACLEASM1 device (/dev/sdb1):
    # ls -l /dev/ORCLASM*
    brw-rw----. 1 oracle dba 8, 17 Dec  6 19:12 ORCLASM1
    Setup and mount /dev/sdb2:
    # mkfs.ext4 /dev/sdb2
    # mkdir /mnt/sdb2
    # mount /dev/sdb2 /mnt/sdb2
    # blkid | grep sdb2
    /dev/sdb2: UUID="c120fb64-02b4-46a0-944a-2ec1b7ab8c18" TYPE="ext4" 
  • 2. Re: RHEL6: udev and ASM
    869799 Newbie
    Currently Being Moderated
    Hi,

    Oracle Linux will not be an option due to company policy (RH only).

    Thanks for the hint with "$parent" - this way I can use partitioned disks as well (successfully tested).

    Is it recommended to use a partition or is it recommended to use the unpartitioned disk (or does is simply not matter at all)?

    btw, found a good page about this subject: http://www.oracle-base.com/articles/linux/udev-scsi-rules-configuration-in-oracle-linux-5-and-6.php


    Thanks a lot,

    Werner
  • 3. Re: RHEL6: udev and ASM
    Dude! Guru
    Currently Being Moderated
    Is it recommended to use a partition or is it recommended to use the unpartitioned disk (or does is simply not matter at all)?
    Apparently it does not matter for ASM as long as the partition is a primary partition.
    http://docs.oracle.com/cd/E11882_01/server.112/e18951/asmprepare.htm

    As far as I'm aware, ASMLib requires the candidate disks to be partitioned. There is a separate OTN forum for Oracle ASM topics.

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