[Lustre-discuss] Can one node mount more than one lustre cluster?

[Andreas Dilger]

On 2011-03-15, at 4:19 PM, Malcolm Cowe wrote:
> On 15/03/2011 17:15, Brian O'Connor wrote:
>> What are the constraints on a client mounting more than one lustre
>> file system?
>> 
>> I realise that a lustre cluster can have more than one file system
>> configured, but can a client mount different file systems from different
>> lustre clusters on the same network?;ie.
>> 
>> Assume a Single IB fabric and two Lustre clusters with separate
>> MGS/MDS/OSS. One lustre is Lincoln and the other is Washington
>> 
>>> list_nids
>> 192.168.1.10 at o2ib
>> 
>>> mount -t lustre lincoln:/lustre  /lincoln
>>> mount -t lustre washington:/lustre /washinton
>> 
>> Is this doable or should they be on separate IB fabrics
> 
> From my understanding, there should only be one MGS for the entire 
> environment (although as many MDTs and OSTs as are required). This is 
> because clients will only communicate with exactly one MGS (and will 
> communicate with the MGS of the last FS mounted) and will only receive 
> updates from the MGS with which it is registered. So, in the above 
> example if there is a change to the "lincoln" file system (e.g. a 
> failover event, some configuration changes), clients will not receive 
> notification.
> 
> There's not an issue with having multiple MGS's on a site, only with 
> mounting lustre file systems from multiple "domains" on the same client, 
> IIRC.

That discussion was had on the list a few months ago, and the correct answer is that it should just work.  The "only use last mounted MGS" problem was fixed at some point, though I don't have the exact version handy.


Cheers, Andreas
--
Andreas Dilger 
Principal Engineer
Whamcloud, Inc.