[dm-devel] not all paths working at boot

[Ed Wilts]

On Thu, Aug 03, 2006 at 02:54:47PM +0100, Dave Holland wrote:
> I have a problem with multipath-tools 0.4.7 (I also tried the latest
> "git" version) running on Debian (mix of stable/unstable), kernel
> 2.6.17-1-amd64-k8, libdevmapper 1.02.07-1, udev 0.093-1. The machine is
> a HP DL385 with QLA2312 FC card.
> 
> Basically, at boot time, multipath does not recognise all the paths. The
> underlying LUNs are visible, the mid-layer allocates /dev/sd* device
> names, but not all the paths are not used:
> 
> newftp1b:~# lsscsi -d | grep ':1]'
> [0:0:0:1]    disk    COMPAQ   HSV110 (C)COMPAQ 3028  /dev/sda[8:0]
> [0:0:1:1]    disk    COMPAQ   HSV110 (C)COMPAQ 3028  /dev/sdi[8:128]
> [1:0:0:1]    disk    COMPAQ   HSV110 (C)COMPAQ 3028  /dev/sdq[65:0]
> [1:0:1:1]    disk    COMPAQ   HSV110 (C)COMPAQ 3028  /dev/sdy[65:128]

The EVAs are strange beasts...  You are running an EVA5000 with firmware
3.028.  That makes it an active/passive controller.  In addition,
although each HSV controller in the EVA has 2 paths to each fabric, only
1 path is actually ever used and the other is there in case the first
fails.   So...your storage is really available on only 1 of the 4 paths.

My personal solution to the EVAs on Linux is to just use the qlogic
failover driver.  It just works.  That's not to say that there isn't a
problem in the multipath software - I'm just saying that you don't need
the multipath suite to make stuff work (in this case).

        .../Ed

-- 
Ed Wilts, RHCE
Mounds View, MN, USA
mailto:ewilts at ewilts.org
Member #1, Red Hat Community Ambassador Program