[gpfsug-discuss] Forcing which node gets expelled?

[Uwe Falke]

Usually, the cluster mgr, receiving a complaint from a node about another 
node being gone, checks its own connection to that other node. If that is 
positive it expells the requester, if not it follows the request and 
expells the other node. 
AFAIK, there are some more subtle algorithms in place if managers or 
quorum nodes are affected. Maybe that can be used to protect certain nodes 
from getting expelled by assigning some role in the cluster to them. I do 
however not know these exactly.

That means: it is not easily controllable which one gets expelled. 
It is better to concentrate on fixing your connectivity issues, as GPFS 
will not feel comfortable in such a unreliable environment anyway. 
 
Mit freundlichen Grüßen / Kind regards

 
Dr. Uwe Falke
 
IT Specialist
High Performance Computing Services / Integrated Technology Services / 
Data Center Services
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From:   Matt Thorpe <matt.thorpe at bodleian.ox.ac.uk>
To:     gpfsug main discussion list <gpfsug-discuss at spectrumscale.org>
Date:   10/25/2016 02:05 PM
Subject:        [gpfsug-discuss] Forcing which node gets expelled?
Sent by:        gpfsug-discuss-bounces at spectrumscale.org



Hi,

We are in the process of diagnosing a networking issue that is causing 2 
of our 6 node GPFS cluster to expel each other (it appears they experience 
a temporary network connection outage and lose contact with each other). 
At present it's not consistent which gets expelled by the cluster manager, 
and I wondered if there was any way to always force a specific node to be 
expelled in this situation?

Thanks and best regards,
Matt

--------
Matt Thorpe  |  BDLSS Systems Administrator
Bodleian Libraries Osney One Building, Osney Mead, Oxford, OX2 0EW
matt.thorpe at bodleian.ox.ac.uk  |  01865 (2)80027
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