Hey guys, im currently doing some research on implementing a high availability system across a WAN link and would like help on certain areas. This is a scaled down project so I might end up using router simulators like gns3, vyatta etc instead real hardware. Also it'll involve two webservers on each side on the WAN(actually both server's will be next to each other so it's more like a fake WAN connection). First, from peoples exprience, what are good choices of WAN connections (frame relay, leased lines etc) for such a system since failover is mostly dependent on the heartbeat monitor? Second, is it even possible to transmit heartbeats across the WAN. I'm sure latency will be a concern but like I said this is scaled down and is for testing.. From read linux-ha.org's tutorials, I found that most setups are on same LAN and a serial(RS232) connection is used between the servers/machines. In precis, I want to be able to achieve failover across a "fake WAN" (if you like). Any responses or even pointers will be appreciated.
Your heartbeat systems must be in he same subnet, and your failover IP must be from that subnet as well. So you cannot have two servers in completely different networks.
Thanks for your reply but I'm inclined to think it's possible or maybe I'm not putting my problem across properly. This is sort of what I'm talking about: http://johnleach.co.uk/documents/heartbeat/index.html
If I understand the document right, the heartbeat boxes (Julius and Caesar as well as Marcus and Aurelius) are in the same subnet.
Yeah, you're right. Guess I read it wrong. Apparently having nodes on different subnets for HA is possible using Quagga/RIP. Check out what I found lately here:http://www.gossamer-threads.com/lists/linuxha/users/52048 I'm thinking of implementing same using a fast converging protocol like OSPF, with two servers on different subnets (but sat next to each other), and a frame relay connection but I'm not quite there yet. Any thoughts, contributions, pointers etc will be appreciated. PS. I guess I should have titled it: How to achieve HA across subnets...
