sve.to

I’m very happy to announce that VirtualBox now supports shared disks. Finally we can attach one disk to several virtual machines and run Oracle RAC and other clusters. As Oracle promised, this feature is released with the next maintenance patch (thanks!).

There is a new image write mode which is called shareable and this options is now available for the commands createhd and modifyhd of VBoxManage. To create new shared image use the command VBoxManage createhd with type shareble, creating shared disk from the GUI is not possible. To mark an existing image as a shared use the command VBoxManage modifyhd with type shareable.

Something important is that only fixed size disks are supported. If the disk is dynamic you will encounter the following error if you try to modify the image:
ERROR: Cannot change type for medium ‘/home/vm/ora11g_shared.vdi’ to ‘Shareable’ since it is a dynamic medium storage unit

There is other minor issue, if the image is already attached to two virtual machines the command modifyhd will also fail:
ERROR: Cannot change the type of medium ‘/home/vm/ora11g_shared.vdi’ because it is attached to 2 virtual machines

And finally, YES it works, I have tested it already!

sve@host:~$ VBoxManage showhdinfo /home/vm/ora11g_shared.vdi
Oracle VM VirtualBox Command Line Management Interface Version 3.2.8
(C) 2005-2010 Oracle Corporation
All rights reserved.

UUID:                     7521f059-1196-4d68-a1a6-cf0082fb446a
Accessible:               yes
Description:          
Logical size:             2048 MBytes
Current size on disk:     2048 MBytes
Type:                     shareable
Storage format:           VDI
In use by VMs:            labs1 (UUID: 25475ff4-70bc-4e2e-aa38-d8fae289273e)
                          labs2 (UUID: e4441f4c-1ef9-42e0-8e54-d2aec2c6cf4f)
Location:                 /home/vm/ora11g_shared.vdi

Regards and happy migration
Sve

I was called that some commands for controlling the cluster and the oracle are not working. This was two node cluster installed with Oracle 10.2.0.4 RAC on HP-UX 11.31 Data Center OE (December 2008) working for a month already.

Arriving at the customer site I noticed that there are a lot (around 500) of hanging racgmain(check) processes which obviously were blocking some of the cluster commands. Errors also can be seen at this log: $CRS_HOME/log/$HOSTNAME/crsd/crsd.log:

2009-04-08 15:22:01.700: [  CRSEVT][90801] CAAMonitorHandler :: 0:Action Script /oracle/ora10g/bin/racgwrap(check) timed
out for ora.ORCL.ORCL1.inst! (timeout=600)
2009-04-08 15:22:01.700: [  CRSAPP][90801] CheckResource error for ora.ORCL.ORCL1.inst error code = -2
2009-04-08 15:25:42.180: [  CRSEVT][90811] CAAMonitorHandler :: 0:Could not join /oracle/ora10g/bin/racgwrap(check)
category: 1234, operation: scls_process_join, loc: childcrash, OS error: 0, other: Abnormal termination of the child

There are a lot of bugs at metalink, but no documents or suggestions how to fix that.

Fortunately we found a solution:

1. Stop CRS on all nodes.

2. Make a copy of racgwrap located under $ORACLE_HOME/bin and $CRS_HOME/bin on all nodes

3. Edit the file racgwrap and modify the last 3 lines from:

$ORACLE_HOME/bin/racgmain “$@”
status=$?
exit $status

to:

exec $ORACLE_HOME/bin/racgmain “$@”

4. Restart CRS and make sure that all the resources are starts.

We were lucky that hit the bug just before the migration and restarting the instances/servers was easy enough. I don’t know if this really solves the problem, but we never hit the bug again.