fdisk, device mapper and asmlib

From: Radoulov, Dimitre <cichomitiko_at_gmail.com>
Date: Fri, 17 Feb 2012 21:34:36 +0100
Message-ID: <4F3EB9DC.8080508_at_gmail.com>

Hi all,
again a 2 node RAC setup on RHEL 5.7 asmlib oracleasm-2.6.18-274.17.1.el5-2.0.5-1.el5
(kernel in use oracleasm-2.6.18-274.17.1.el5)
Linux native multipath - device mapper
asm scan order: "mpath_string dm"
asm exclude: "sd"

We're facing the following issue:

  1. Delete an existing Linux partition from a LUN on external storage
    (SAN) using fdisk
    (the partition was previously marked as an asm disk with
    /usr/sbin/oracleasm createdisk ... and later that label was removed with /usr/sbin/oracleasm deletedisk ...).
  2. A new partition was added with fdisk (using a non-default offset for the first sector).
  3. The new partition was marked as an asm disk with /usr/sbin/oracleasm createdisk again.
  4. /usr/sbin/oracleasm lisdisks on the first node displays the expected result (the output includes the newly created asm disk).
  5. /usr/sbin/oracleasm scandisks was issued on the second node, followed by /usr/sbin/oracleasm listdisks. The new asm disk was missing!

We tried the following workaround:

we stopped all Oracle processes and we tried to unload and reload the asmlib driver:

     /etc/init.d/oracleasm restart (we tried stop and start too)

    The new asm disk was still missing.

  We also tried:

    /usr/sbin/oracleasm exit
    /usr/sbin/oracleasm init

   The init just doesn't seem to work after exit ...    I believe the second command sequence is not even documented,    so for now you can just ignore it :)

Rebooting the node seems to fix the issue (everything works as expected).

The case is 100% reproducible (we tried several times :)).

I'll open an SR on Monday, but ..., a part from the "do not use asmlib" advice,
am I missing something obvious?

Best regards

Received on Fri Feb 17 2012 - 14:34:36 CST

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