Created attachment 448295 [details]
Informational syslog message indicating label overrides device

Description of problem:
When user specifies both quorum label and quorum device (ccs allows this), the user isn't notified that the label will override the device when searching through disks for the quorum partition.  This can mislead the user into thinking that qdiskd will in fact use the quorum device they specified.

This can have serious consequences when the user intends qdiskd to use a specified a multipath device such as "/dev/mapper/qdisk", but in actuality qdiskd will just use the first device it finds with matching user specified label (for example "/dev/dm-17").  According to RedHat documentation, when using multipath, one should always use /dev/mapper/xxx devices to ensure proper path failover, rather than /dev/dm-xx or /dev/mpath/xxx devices.

Version-Release number of selected component (if applicable):
cman-2.0.115-34.el5.x86_64 from RHEL 5.5

How reproducible:
Specify both device and label in the quourmd stanza of the cluster configuration file.  ex:
<quorumd interval="2" min_score="1" tko="15" votes="1" device="/dev/mapper/qdisk" label="rhcsqdisk" status_file="/var/log/qdisk.status" log_level="7" log_facility="local5">
</quorumd>

Steps to Reproduce:
1.  when using multipath for quorum disk, define both label="xxx" and device="/dev/mapper/xxx" in cluster.conf
2.  restart qdiskd service
3.  lsof | grep qdiskd  will show qdiskd using a /dev/dm-xx device instead of the /dev/mapper/xxx device as user intended.
  
Actual results:
/dev/dm-xxx

Expected results:
/dev/mapper/xxx

Additional info:
Attached patch will syslog an informtional message indicating that the Qurom Label will override the Quorum Device when searching for the quorum partition.  This will alert the administrator to the unintended result and allow the administrator to adjust the cluster configuration removing the label and only defining device, especially when the intent is to ensure qdiskd has proper path failover such as a multipathed /dev/mapper/xxx device.