On Jun 26, 2014, at 8:53 AM, Phil Mayers <p.mayers@imperial.ac.uk> wrote:
A lot depends on how stable the routing is, and how many next-hops are present, as well as how your routers hash between multiple next-hops e.g. ip or ip + port.
Yeah, I’m just starting to look into this. We’re on Juniper gear (sorry Arran!) and I think it tries to maintain a stable path for the same IPs. In the worst case, we could just set them up with a route preference so everything goes to the primary until failure (rather than trying to load-balance). Our site isn’t big enough to have a load problem so this is mostly for availability.
Basically - if you're going to do this, ensure traffic to the anycast IP only reaches one server from every point during stable operation. During a routing change - which is presumably a failure event - packets will flow differently, but that doesn't matter because it's a failover event anyway.
Exactly. So long as the happy path is stable we can deal with a little weirdness around failures, as they would cause hiccups with regular NAS failover anyway. I’ll add it to my to-do list, then, and see if we can get it running. Thanks for the advice! Jason -- Jason Healy | jhealy@logn.net | http://www.logn.net/