On 03/14/2014 02:13 PM, Mike Snitzer wrote: > Yeah, not sure why single path scsi_debug "just works", maybe it is a > "feature" of the older multipathd I have kicking around?, but for basic > data path testing scsi_debug is a quick means to an end. I can look > closer at _why_ it gets multipathd in a bit. But maybe Ben or Hannes > will have quicker insight? Do you have find_multipaths set in multipath.conf? It defaults to off. If it's enabled then multipath will only create maps for WWIDs it already knows about (listed in /etc/multipath/wwids) unless there are at least two devices with the same WWID or the user forces the operation: Mar 17 12:26:50 | checking if sdm should be multipathed Mar 17 12:26:50 | wwid 35333333000000000 not in wwids file, skipping sdm Turn it off and multipath will happily map a single path scsi_debug for me: # multipath create: mpathg (35333333000000000) undef Linux,scsi_debug size=1.0G features='0' hwhandler='0' wp=undef `-+- policy='round-robin 0' prio=1 status=undef `- 8:0:0:0 sdm 8:192 undef ready running Iirc this is enabled on at least some current distros by default to avoid creating maps for USB keys and the like. Regards, Bryn. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
