some time ago a friend showed me his concept of a virtualized web application:
- 2 Apaches - load-balanced via IPVS/LVS
- 2 MySQL - HA via DRBD and Heartbeat
The virtualized machines all run under the same hypervisor on the same host. So I was wondering if this setup is reasonable because I see no advantage.
- Host is SPOF
- Load-Balancing via IPVS? Host CPU is the bottleneck anyway or can 2 virtualized CPUs handle more interrupts than the Host CPU alone?
- MySQL HA? Isn't it faster for the hypervisor restarting a crashed guest than failover via DRBD etc...?
I don't see any advantage in network load-balancing under the same hypervisor since network I/O between guests is mapped memory anyways and therefore fast.
Any ideas, suggestions?
For me it is just overhead and single, beefier guests make more sense...