POT = Possibly Off topic
<snippage>
: Likewise with sessions. Even if you load balance across multiple machines
: you don't need to access a session database on every request. Most load
: balancing systems have something so they'll send the seme "session"
: (typically ip address) to the same backend server for N seconds as long as
: the backend server is up of course.
:
: You can then put a daemon on each backend server as a local buffer and
: cache between the httpds and the session database. This daemon can even
: load balance the session information over several databases if it's
: needed.
:
: viola, a lot less "real time" lookups in the database needed and a lot
: less direct connections.
ironically I was thinking the same thing today (I may need to load ballance
3 webservers to one DB server).
But - is this model not transaction safe ? - It may save alot of DB use and
hence be alot quicker - but what if the webserver "disappears" halfway
through an IP based load ballanced "sesssion" - a potential source of
failure - something which a load ballancer is supposed to help with..
Also if the loadballance goes south, and a secound takes over does it have
the same IP based session info (probably not - but could be wrong ...) -
hence another potential source of failure.
If your model can accept this then fine - but this would not work in a
{few|many} ecomerce apps as session management is critical.
What do you think ?
Greg Cope
:
:
: - ask
:
: --
: ask bjoern hansen - <http://www.netcetera.dk/~ask/>
: more than 70M impressions per day, <http://valueclick.com>
:
:
