[gpfsug-discuss] GPFS heartbeat network specifications and resilience

Sobey, Richard A r.sobey at imperial.ac.uk
Fri Jul 22 09:36:40 BST 2016


Hi Ash

Our ifcfg files for the bonded interfaces (this applies to GPFS, data and mgmt networks) are set to mode1:

BONDING_OPTS="mode=1 miimon=200"

If we have ever had a network outage on the ports for these interfaces, apart from pulling a cable for testing when they went in, then I guess we have it setup right as we've never noticed an issue. The specific mode1 was asked for by our networks team.

Richard

-----Original Message-----
From: gpfsug-discuss-bounces at spectrumscale.org [mailto:gpfsug-discuss-bounces at spectrumscale.org] On Behalf Of Ashish Thandavan
Sent: 21 July 2016 11:26
To: gpfsug-discuss at spectrumscale.org
Subject: [gpfsug-discuss] GPFS heartbeat network specifications and resilience

Dear all,

Please could anyone be able to point me at specifications required for the GPFS heartbeat network? Are there any figures for latency, jitter, etc that one should be aware of?

I also have a related question about resilience. Our three GPFS NSD servers utilize a single network port on each server and communicate heartbeat traffic over a private VLAN. We are looking at improving the resilience of this setup by adding an additional network link on each server (going to a different member of a pair of stacked switches than the existing one) and running the heartbeat network over bonded interfaces on the three servers. Are there any recommendations as to which network bonding type to use?

Based on the name alone, Mode 1 (active-backup) appears to be the ideal choice, and I believe the switches do not need any special configuration. However, it has been suggested that Mode 4 (802.3ad) or LACP bonding might be the way to go; this aggregates the two ports and does require the relevant switch ports to be configured to support this. 
Is there a recommended bonding mode?

If anyone here currently uses bonded interfaces for their GPFS heartbeat traffic, may I ask what type of bond have you configured? Have you had any problems with the setup? And more importantly, has it been of use in keeping the cluster up and running in the scenario of one network link going down?

Thank you,

Regards,
Ash



--
-------------------------
Ashish Thandavan

UNIX Support Computing Officer
Department of Computer Science
University of Oxford
Wolfson Building
Parks Road
Oxford OX1 3QD

Phone: 01865 610733
Email: ashish.thandavan at cs.ox.ac.uk

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