[gpfsug-discuss] Mixing RDMA Client Fabrics for a single NSD Cluster

[Simon Thompson]

I think what you want is to use fabric numbers with verbsPorts, e.g. we have two IB fabrics and in the config we do thinks like:

[nodeclass1]
verbsPorts mlx4_0/1/1
[nodeclass2]
verbsPorts mlx5_0/1/3

GPFS recognises the /1 or /3 at the end as a fabric number and knows they are separate and will Ethernet between those nodes instead.

Simon

From: <gpfsug-discuss-bounces at spectrumscale.org> on behalf of "Stephan.Peinkofer at lrz.de" <Stephan.Peinkofer at lrz.de>
Reply-To: "gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org>
Date: Thursday, 19 July 2018 at 15:13
To: "gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org>
Subject: [gpfsug-discuss] Mixing RDMA Client Fabrics for a single NSD Cluster

Dear GPFS List,

does anyone of you know, if it is possible to have multiple file systems in a GPFS Cluster that all are served primary via Ethernet but for which different “booster” connections to various IB/OPA fabrics exist.

For example let’s say in my central Storage/NSD Cluster, I implement two file systems FS1 and FS2. FS1 is served by NSD-A and NSD-B and FS2 is served by NSD-C and NSD-D.
Now I have two client Clusters C1 and C2 which have different OPA fabrics. Both Clusters can mount the two file systems via Ethernet, but I now add OPA connections for NSD-A and NSD-B to C1’s fabric and OPA connections for NSD-C and NSD-D to  C2’s fabric and just switch on RDMA.
As far as I understood, GPFS will use RDMA if it is available between two nodes but switch to Ethernet if RDMA is not available between the two nodes. So given just this, the above scenario could work in principle. But will it work in reality and will it be supported by IBM?

Many thanks in advance.
Best Regards,
Stephan Peinkofer
--
Stephan Peinkofer
Leibniz Supercomputing Centre
Data and Storage Division
Boltzmannstraße 1, 85748 Garching b. München
URL: http://www.lrz.de

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