Re: Dangling UDEV links after removing FC LUNs

On Sat, Dec 03, 2016 at 04:20:05PM +0000, admin wrote:
> Dear list,
> we're using Q-Logic QLE2562 Fibre Channel adapters (qla2xxx driver) against a HPE 3PAR 7400c storage array in an OpenStack environment. The OpenStack 3PAR driver manages volume attachments from the array to the servers. There is 4 path multipath to every volume.
> 
> As the LUNs are removed, sometimes udev does not remove all links, particularly in /run/udev/links and /dev/disk/by-path. The symptoms are multiple records in one by-path directory under /run/udev/links, broken links to no longer attached luns in dev/disk/by-path and links between wrong LUNs and scsi devices there. I'm getting "multipathd: udev trigger error" in syslog.
> 
> OpenStack relies on these links. When another volume is attached using a LUN that has these leftover links and it happens that it is the first of the 4 paths, OpenStack incorrectly identifies the volume and attaches the same volume to multiple instances, leading to data loss.
> 
> What could be causing this behavior?
> 
> Ubuntu version 14.04
> Linux version Ubuntu 4.4.0-47.68~14.04.1-generic 4.4.24
> udev 204-5ubuntu20.19

Please contact Canonical for support of their old kernel release and
udev package, there's not much the community can do about that, sorry.

Good luck!

greg k-h