Scaling IP address handling in CTDB

WhoMartin Schwenke
WhereSambaXP 2014, Göttingen, Germany
WhenMay 2014

CTDB can use a pool of public IP addresses to provide load balancing and high availability. We have recently become aware that handling a large number of IP address changes in CTDB does not scale well. This is because each change is handled by forking a copy of the CTDB daemon and running a large number of scripts. We started working a sequence of patches to CTDB to make public IP address handling more scalable. In the process we found some surprising CTDB bugs and discovered a helpful Linux networking feature. This "hacker's tale" describes the proposed improvements and the things we learned when implementing some of them.

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