fdisk, device mapper and asmlib

  • From: "Radoulov, Dimitre" <cichomitiko@xxxxxxxxx>
  • To: ORACLE-L <oracle-l@xxxxxxxxxxxxx>
  • Date: Fri, 17 Feb 2012 21:34:36 +0100

Hi all,
again a 2 node RAC 11.2.0.3.1 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
Dimitre






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