[Lustre-discuss] Lustre on mpath devices

[Cliff White]

Klaus Steden wrote:
>> That depends...  It depends on what "blkid -t LABEL={fsname}-OST0001"
>> returns.  It _should_ be smart enough to return the DM device, but
>> it is prudent to make sure of this.  There shouldn't be any problem
>> with mounting the Lustre filesystems by LABEL= (which is one reason we
>> moved to a mount-based setup).
>>
> Hi Andreas,
> 
> I just checked out my local system and it's returning a regular device name
> (/dev/sdh, or /dev/sdi, depending on the label) and a unique UUID, but then
> I didn't enable multipath when I built the FS.
> 
> If I avoid using the /dev name, is it still possible to build failover
> properly if I'm not using the multi-path framework? If it's not, is a
> rebuild of the filesystem required in order to enable multi-path support?

Hmm. Let's be clear here. You are talking about node failover, which 
would be managed by some sort of HA framework (Heartbeat, etc)
For node failure, again you only have to be sure the disk is reachable 
by both nodes (shared) and that each node has a consistent method for 
identifying the shared spindle. Mulitpath shouldn't matter to Heartbeat,
it will use the Lustre mount command which supports labels.
cliffw

> 
> Sorry to keep firing questions at you, I'm trying to make sure I've got all
> the bases covered for failover.
> 
> thanks again,
> Klaus
>  
> 
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