First some background info: I have a Infortrend A16F-R2211 diskarray connected to two independent Qlogic 5200 to which I also have connected a couple of machines with two Exmulex LP10000-M2 HBA's, all running CentOS 4.3. The Infortrend box have four SFP-ports which is connected to two redundant controllers which each have two "channels". In the Infortrend-box you can configure logical drives (and optionally logical volumes) which then can be mapped to LUNs on each channel. Each logical drive can only be assigned to one controller, but in case of a controller failure, the other controller will take over the logical drives from the failed controller. A LUN mapped to a logical drive will have the same WWNN on both channels, but different WWPN. Now to my problem: I was hoping to be able to set up a fault tolerant solution using multipathing so that if a controller, fabric, fiber-cable or HBA fails, a filesystem is still accessible on the hosts using device-mapper-multipath. This works ok if a fabric, fibre-cable or HBA fails, but when a controller fails all paths become "stale". This seems to be due to the fact that the lpfc-driver maps the LUNs to different target numbers after a controller failure, but only if the disks are "active" (i.e mounted) If I do 'cat /proc/scsi/lpfc/*' when everything is ok, it looks like this: lpfc0t00 DID 010025 WWPN 21:00:00:d0:23:0b:01:91 WWNN 20:00:00:d0:23:0b:01:91 lpfc1t00 DID 020025 WWPN 22:00:00:d0:23:0b:01:91 WWNN 20:00:00:d0:23:0b:01:91 At the same time, the output from 'multipath -ll' is: mpath1 (3600d0230000000000b01910b4d313400) [size=97 GB][features=0][hwhandler=0] \_ round-robin 0 [prio=0][active] \_ 1:0:0:0 sde 8:16 [active][ready] \_ 2:0:0:0 sdf 8:32 [active][ready] If I manually fail the controller, while having the filesystem mounted the output from 'cat /proc/scsi/lpfc/*' looks like this: lpfc0t01 DID 010025 WWPN 21:00:00:d0:23:0b:01:91 WWNN 20:00:00:d0:23:0b:01:91 lpfc1t01 DID 020025 WWPN 22:00:00:d0:23:0b:01:91 WWNN 20:00:00:d0:23:0b:01:91 Due to this both paths fails and the filsystem is inaccessible I've tried: echo 1 >/sys/class/scsi_device/1:0:0:0/device/delete echo 1 >/sys/class/scsi_device/2:0:0:0/device/delete echo "- - -" > /sys/class/scsi_host/host1/scan echo "- - -" > /sys/class/scsi_host/host2/scan But this will render me new sdb/sdc at 1:0:1:0/2:0:1:0 which isn't what I need. When I "fix" the failed controller, and the diskarray returns to two-controller-mode, 'cat /proc/scsi/lpfc/*' looks like this again: lpfc0t00 DID 010025 WWPN 21:00:00:d0:23:0b:01:91 WWNN 20:00:00:d0:23:0b:01:91 lpfc1t00 DID 020025 WWPN 22:00:00:d0:23:0b:01:91 WWNN 20:00:00:d0:23:0b:01:91 If I don't have the filsystem mounted (and not mapped via dm-multipath either), but accessible as sdb/sdc, and then manually fail the controller, the targetnumber isn't renumbered. Now my question: Is there anything I can do to "fix" this, or do I have to "accept" that this hardware/software-combination can't do what I want? I'm running CentOS 4.3 on x86_64, running kernel 2.6.9-34.ELsmp which has a lpfc-driver identifying itself as "Emulex LightPulse Fibre Channel SCSI driver 8.0.16.18" -- Roger Håkansson - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
