So you want mod_cluster to add a cookie with the node name (or a hash) to make the routing, correct?
The actual way of mod_cluster is a kind of "common" way for doing sticky sessions (and group failover) for example mod_jk and mod_proxy_balancer are doing the same.
which would i think speed up a lookup, since mod_cluster doesn't have to anymore parse out cookie name
You mean it would eliminate call to
route = strchr(sessionid, '.')
but instead add a whole new cookie that would have to be parsed out from the HTTP request? Sorry, but I don't see the performance improvement, but degradation: there is more parsing from the request and the HTTP request would get bigger by the extra cookie name length.
Nevertheless, all of these are IMHO negligible performance-wise, it's better to stay "standard" and keep doing what others are doing.
i've been looking at different implementations, and actually i cannot find this being a standard, for example AWS allows you to either create a load balancer cookie, or use application cookie, and application cookie does not need to have a route in it, so application is not aware of a cluster at all, and f5 for example not using this methodology all together. also mod_proxy_balancer is not appending anything to existing cookie, nor parsing it, it just sets a routeid cookie.
i would say that mod_cluster is actually not following "standards" in this case, and making clustering implementation very application specific, however we could be trying to make it more independent from application ( i realize it is dynamic clustering, so we can't make it completely independent ).