[gpfsug-discuss] Question about subnets parameter and remote cluster mounts

[Achim Rehor]

Dear Leonardo,

you will find a description in the Concepts, Planning, and Installation
Guide in the GPFS daemon communication section, explaining how the
startup mechanism works. 
The Administration Guide contains an explanation on MROTs specifics for
the subnets usage (Chapter 17 in the 5.1.7. version) 
Chapter 33 focuses on remote cluster mounts and contains examples.

Basically, the node join triggers the compare and the matching, thus a
client clusters node uses it's subnets configuration (including the
remote clusters clustername) to initiate the connection. 
On the storage cluster you can also diffentiate your existing subnets
for use with separate remote mounting clusters. I would recommend still
to do it on both, just to be precise. 

Initially the idea (as can be seen in the examples in Chapter 33) was
to force the daemon communication to the storage NSD servers to use the
'high speed' network, rather than the lower bandwidth common admin
network. 


-- 
Mit freundlichen Grüßen / Kind regards

Achim Rehor

Technical Support Specialist S​pectrum Scale and ESS (SME)
Advisory Product Services Professional
IBM Systems Storage Support - EMEA

Achim.Rehor at de.ibm.com 				+49-170-
4521194	 							
IBM Deutschland GmbH 


-----Original Message-----
From: Leonardo Sala <leonardo.sala at psi.ch>
To: gpfsug main discussion list <gpfsug-discuss at gpfsug.org>, Achim
Rehor <Achim.Rehor at de.ibm.com>
Subject: [EXTERNAL] Re: [gpfsug-discuss] Question about subnets
parameter and remote cluster mounts
Date: Wed, 03 May 2023 16:58:12 +0200

 Dear Achim, thanks! My point is: in case of a remote cluster mount,
e. g. CL2 mounting CL1 storage, where should I specify the subnets
parameter: 1) on CL2 (client cluster) 2) on CL1 (storage cluster) 3) on
both CL1 and CL2 I might have to change
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 #pfptBannerzu381sx { all: revert !important; display: block !important; visibility: visible !important; opacity: 1 !important; background-color: #D0D8DC !important; max-width: none !important; max-height: none !important } .pfptPrimaryButtonzu381sx:hover, .pfptPrimaryButtonzu381sx:focus { background-color: #b4c1c7 !important; } .pfptPrimaryButtonzu381sx:active { background-color: #90a4ae !important; }Dear Achim,
thanks! My point is: in case of a remote cluster mount, e.g. CL2
mounting CL1 storage, where should I specify the subnets parameter:
1) on CL2 (client cluster)
2) on CL1 (storage cluster)
3) on both CL1 and CL2
I might have to change this parameter on a production system, and as it
needs a restart I would like to be sure I change it only where
necessary
Thanks again!
cheers
leo
Paul Scherrer Institut
Dr. Leonardo Sala
Group Leader Data Analysis and Research Infrastructure
Deputy Department Head a.i Science IT Infrastructure and Services department
Science IT Infrastructure and Services department (AWI)
WHGA/036
Forschungstrasse 111
5232 Villigen PSI
Switzerland

Phone: +41 56 310 3369
leonardo.sala at psi.ch
www.psi.ch
On 5/3/23 16:40, Achim Rehor wrote:
 
> correct, there is no need to put client and storage into different
> subnets, 
> and it is also not necessary to specify the subnet parameter at all,
> when they share the same network. 
> 
> The subnets parameter is very helpful, though, if you are using
> multiple networks, and want to use specific ones for communication with
> one or the other remote cluster.
>