[DRBD-user] Double homicide, can DRBD help?

nathan at robotics.net nathan at robotics.net
Mon Sep 15 16:45:25 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

My nice cisco 3750 switch crashed yesterday, both DRBD servers noticed the 
lack of connectivity, then came back when the switch rebooted and auto 
resolved the split brain. However I am running CLVM on top of DRBD and 
fencing was not happy with the loss of connectivity and each server 
decided to shoot each other in the head.

Each server is connected with gig ethernet as well as infiniband and the 
cluster and I believe fencing can be configured to use two interfaces. Is 
there any way to configure DRBD to use BOTH IP address? The ability to 
use two networks for DRBD would help in many ways.

The 2nd question is, assuming that DRBD can not be configured to use two 
networks, how safe is it for me to configure fencing to use both network 
and have DRBD run as primary/primary for a while in split brain? The boxes 
are used for XEN and each server only reads/writes to a unique file using 
tapaio. My guess is not long before blocks would get messed up beyond 
repair even if they are each accessing unique files, but I am not sure on 

Thought about using some sort of routing protocol between the boxes, but 
they all look two slow to work in this application.

Nathan Stratton                                CTO, BlinkMind, Inc.
nathan at robotics.net                         nathan at blinkmind.com
http://www.robotics.net                        http://www.blinkmind.com

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