this is a reply to kevin duffeys questions regarding sessionfailover that i
thought might be of interest to others on the list
----- Original Message -----
From: "Morten Wilken" <[EMAIL PROTECTED]>
To: "Duffey, Kevin" <[EMAIL PROTECTED]>
Sent: Wednesday, August 22, 2001 12:25 PM
Subject: Re: Orion and session fail-over..
>
> ----- Original Message -----
> From: "Duffey, Kevin" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Wednesday, August 22, 2001 2:57 AM
> Subject: Orion and session fail-over..
>
>
> hi kevin, as i said in my post, what i did was to add the load-on-startup
to
> to web-app tag... and then i found that the other servers started
recieving
> right away.
> i run all my apps in the default web site.... i dont know if that factors
> into it aswell.. i suppose i shouldn't.
> im not sure which of my posts you're referring to as i posted a couple of
> them about this, but i followed the clustering howto from orion, plus i
> addede the load-on-startup=true attribute.
> you could post me your configs and i could have a look :-)
>
> as for how orion implements loadbalancing, i wrote a small multicast
client
> and set it up to listen to the port, plus i added the -debug flag to see
> what really went on, and it seems that it replicates the object in the
> session when you change it, and not the entire session. and ofcourse it
only
> replicates it to its own clusterisland.
> this would mean tht if you had a 500mb session (which i wouldnt recommend
> :-)) then either you have a bunch of objects that each is replicated when
> they're accesed, or you have a 500mb object in your session, in which case
> it would replicate it all.
>
> another thing that i had to change in my original design was that i had to
> explicitly set the session object in order for it to be flagged for
> replication ie:
>
> not:
>
> object a =session.getAttribute("someObject);
> a.method();
>
> but:
> object a =session.getAttribute("someObject);
> a.method();
> session.setAttribute("someObject, a);
>
> hope some of this helps, and if not please write me again :-)
> anf good luck with your book
>
> sincerely
> Morten Wilken
> > Hi there,
> >
> > I just posted a message to the list about clustering. I happened to be
> > deleting the 7000 emails I have in archive of the Orion-list and decided
> to
> > search for clustering. I cam across your thread, and I am having EXACTLY
> the
> > same problem you are. The only difference is, I have the load-on-startup
> in
> > my <web-site> tag, and I am still seeing the same results. One server
> shows
> > the "Sending..." the other one shows nothing. Not sure if it is supposed
> to
> > or not. I would list my config, but its at home. I am hoping you can
help
> me
> > figure this out as I am writing a chapter on scalability using a simple
> cart
> > based web-app, and I want to test it for session fail-over, and explain
> how
> > it works in this chapter.
> >
> > In my email to the list I am trying to find out how in general servlet
> > containers fail over. When you use the setAttribute() call, does it copy
> the
> > entire session of that user to the other server(s) in the cluster? Or
does
> > it just copy the one object and the other server(s) are smart enough to
> > insert it into the right session? OR..worse..does it copy ALL sessions
of
> > all users to the other servers??!! If so, what happens when you have a
> > session of 500MB of objects..does it take like 2 minutes to replicate
the
> > session, bring Orion to a crawl, etc?
> >
> > Thanks for your help and info.
> >
> >
>
