kern/169647: gmultipath fails to detect missing module

[Florian Heigl]

>Number:         169647
>Category:       kern
>Synopsis:       gmultipath fails to detect missing module
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Jul 04 15:30:04 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Florian Heigl
>Release:        9.0-RELEASE-p3
>Organization:
Mathias Kettner GmbH
>Environment:
FreeBSD  9.0-RELEASE-p3 FreeBSD 9.0-RELEASE-p3 #0: Tue Jun 12 02:52:29 UTC 2012     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64

>Description:
If you don't have the geom_multipath module loaded, gmultipath list -a (and all other options) will report an error that the command is not available.

# gmultipath list -a
gmultipath: Command 'list' not available.
# gmultipath status
gmultipath: Command 'status' not available.


Once loading the module the commands will magically start to work.

I would beg you for a more useful error handling.
Yes, I know there might be some corner-cased reason since geom is a framework and so the command is in fact not available without the module.
Do not want.

gmultipath list should either return an empty list or an actual error (module not loaded!) here.


I would like to add gmultipath monitoring to our software (and by that, to nagios), but it's almost impossible with unreliable output like this.


I can't workaround this using kldstat, since it might be in-kernel, not a module.
How can I ask geom if it has multipathing features running?

I filed this as a medium bug since multipathing is amongst the most critical parts of an OS (many times more important than raid, since critical data will not be on a local raid...) and there needs to be a reliable means of querying it.
>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: