[Lustre-discuss] SLES11, lustre 1.82 with lvm and multipathing problems

[Andreas Dilger]

On 2010-06-16, at 03:23, lustre wrote:
> we have one LUN on our MGS|MGT Server.
> The LUN is availible over two pathes.
> ( Multipathing with OS embeded rdac driver, SLES11)
> 
> Now we switched the controller on the storage to simulate a path failover:
> after that the MDT Device is unhealthy:
> multipath -ll 3600a0b80005a7215000002034b952b00 dm-10 SUN,LCSM100_S
> and we can not remount the filesystem -> the filesystem is not writeable
> We can see this in /var/log/messages, as there is a warning about this filesystem beeing in read-only mode.

This is a problem below Lustre.  It appears the multipath configuration cannot handle a path failure without reporting IO errors to the filesystem.  Either the command you are using to test path failures is not doing what you expect, or the multipath is not working correctly (e.g. your second path is not actually working, or it is cabled incorrectly, or the multipath driver is broken).

You need to fix this, and then Lustre should work.  I'm assuming that you configured the MDT device correctly to use the right block device, and it isn't accidentally using the raw underlying device and avoiding the multipath.

Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.