Re: NIC and HBA based multipathing

[Mike Christie <michaelc@cs.wisc.edu>]

Scott Moseman wrote:
> Thanks for the follow-up.  I have each initiator setup with access to
> the SAN.  The NIC is accessing /dev/sdb and the HBA is accessing
> /dev/sdc.  I can mount either (or both) and access the data on the SAN
> volume.

Yeah, the iscsi bits looks fine. You will have a /dev/sdX for the nic 
and one of the HBA.

When you start multipath, multipath should then create one multipath 
device from those two scsi ones.

> 
> # rpm -qa | grep multipath
> device-mapper-multipath-0.4.5-16.1.RHEL4
> 
> # /etc/init.d/multipathd status
> multipathd (pid 15929) is running...
> 
> I'm following the instructions on Red Hat's KB to setup the
> multipath.conf file.  The modprobes were successful, the service
> started, but...
> 
> # multipath -v2
> error calling out /sbin/scsi_id -g -u -s /block/sda
> 
> ...with /dev/sda being my physical hard drive.  dmesg output says:
> 
> device-mapper: dm-multipath: error getting device
> device-mapper: error adding target to table

So are you asking about the errors from /dev/sda being accessed by 
multipath, or are you looking for help on adding the iscsi disks to a 
multipath device or both :)