Hi Sebastian, On Sat, Apr 14, 2012 at 05:49:11PM +0200, Sebastian Fohler wrote: > I use HAPROXY on a ESXi 5.0 VM. To be exact I use two of them to load > balance. > My greates problem seems to be the finetuneing and the ability to get > the VM's stable enough. > For some reasons my haproxy instances are always giving up on estimated > 2500 connections. > Is there some howto or configuration guide for haproxy on vm's?
The VMs are independant on the number of concurrent connections. VMs impact network processing and CPU usage, so the data rate, the packet rate and the connection rate count much more than anything else. The most important thing to keep in mind when running a low latency workload such as a load balancer or a proxy on a VM is that it must absolutely run on a dedicated CPU. If the hypervisor steals the CPU for 10ms from time to time, you get an extremely slow VM with poor performance. It is also important that you use the native drivers as much as possible, and not any emulation (eg: use vmxnet and not e1000). You obviously want to disable the vmballoon mechanism which is used by the hypervisor to steal your VM's memory. And you need to run good NICs in your hardware. It might seem obvious, but I've already seen a realtek NIC been used for this because it was available on the mainboard ! You should provide more information (#CPUs, memory, kernel version, loaded modules, etc...) for more help. Hoping this helps, Willy
