Hello,
I enjoyed Theo's talks at ApacheCon, and they got me thinking about the
nature of Spread and the broader uses of multicast in a web cluster. Theo
pointed out that mod_backhand does balancing based on load, while most
hardware balancers do not. What I wonder is, given the latency in the load
information, does this truly do a better job of evenly distributing load
than random distribution, or methods like "least connections" that some
hardware balancers provide? I know it would with a very heterogenous
cluster, but what about in the typical case where all the machines are
basically equivalent?
On a related note, I'm thinking of implementing Spread as a storage
mechanism for Apache::Session, the popular mod_perl module for storing
session data. My concern is that unless Spread can distribute the data to
all machines in the cluster very quickly, you'd still have to use sticky
load-balancing in order to make sure the user reaches a machine that has his
data. Can Spread keep up with the rate needed to handle things like robots
or quick reloads?
Apologies if I should be asking these questions on some Spread mailing list.
Just point me to it, if that's the case.
- Perrin
I enjoyed Theo's talks at ApacheCon, and they got me thinking about the
nature of Spread and the broader uses of multicast in a web cluster. Theo
pointed out that mod_backhand does balancing based on load, while most
hardware balancers do not. What I wonder is, given the latency in the load
information, does this truly do a better job of evenly distributing load
than random distribution, or methods like "least connections" that some
hardware balancers provide? I know it would with a very heterogenous
cluster, but what about in the typical case where all the machines are
basically equivalent?
On a related note, I'm thinking of implementing Spread as a storage
mechanism for Apache::Session, the popular mod_perl module for storing
session data. My concern is that unless Spread can distribute the data to
all machines in the cluster very quickly, you'd still have to use sticky
load-balancing in order to make sure the user reaches a machine that has his
data. Can Spread keep up with the rate needed to handle things like robots
or quick reloads?
Apologies if I should be asking these questions on some Spread mailing list.
Just point me to it, if that's the case.
- Perrin