[imp] IMP php database session problem

[Sheeri Kritzer]

Quoting Joseph Lo <jlo@pgicanada.com>:

> The problems with session was caused by a load balancing server.  Traffic is
> directed from the load balancing server to two identical web servers.  The
> previous session were not detected when users were directed to the opposing
> web server which the session was not started on.

Dear Joseph,

Here at Tufts University we recently put 3 IMP servers behind a load balancer 
(we did it last Wed., in fact).  I don't know much about load balancing 
hardware (we have a Network Operations Group that set up the load balancer for 
us and told us to configure the machines to use it), but I do know that we have 
enabled our load balancer to set the session to "sticky" (that's a technical 
term).

Basically, this means that a person goes to http://webmail.tufts.edu and they 
get redirected to machine1, machine2 or machine3.  Let's say it goes to 
machine2.  After that, any time it does anything in webmail (until the user 
closes the browser, I think) it is redirected to machine2.

> To solve this problem I decided to save my session in the database(mysql)
> which sits in a seperate server which is connected to both webservers.  I
> had to switched the session.savehandler = user in the php.ini file.  After
> this my php sites worked fine.  Unfortunately, IMP no longer worked.  I'm
> not too sure how to configure IMP to work with database sessions.  I've
> tried to add my database session functions to the php files where sessions
> are used which did not
> work.  I've looked through previous posting and faq to try to figure this
> out with little luck.

That's a kludge, although we are also working to having a shared mysql server 
for horde and IMP preferences and turba addressbooks.  (if anyone has advice on 
that, let me know...

-Sheeri Kritzer
Systems Administrator
University Systems Group
Tufts University
617-627-3925
sheeri.kritzer@tufts.edu