Thanks for reply. The paper I read explains the load balancing and fault tolerance very well by using mutiple Jserv. But it left out the front end apache server. I am really curious about software solution (not hardware router solution) to this. Any pointers to this? Thanks Bing At 12:56 PM 6/9/99 -0700, you wrote: >> I recently read a white paper about apache load balancing and fault >> tolerance, but I still have some questions about it. >> >> It says apache using DNS round robin to assign the actual IP to the server, >> how does this work? > >yes. > >> Does all the DNS server today support this? > >yes > >> Let's see I have two machines, A and B, with same name assigned by DNS. A >> client connection comes in, due to round robin, machine A gets pick up. >> Then subsequent call should always talk with A, shouldn't it? Now if A >> fails, what will happen to the client? Will it be connected to B? How? > >that is why round robin dns doesn't work very well. ;-( > >what you should have is a single machine with multiple jserv servlet engines >(ie: the java portion) on the back end. if one of the servlet engines goes >down, mod_jserv will figure that our and stop sending requests to it. > >web client -----> apache -----> mod_jserv -----> servlet engine 2 > | > | > v > servlet engine 1 > >if you need more redundancy on the front end machine, there are tricks that >you can do with multiple apache's proxying the information to other servers >as well as router tricks (check out www.packeteer.com...we have one on loan >here at clear ink and their boxes rock!). > >for serious redundancy, you can also have another machine that is not >plugged in that can replace the "apache" portion of the diagram above by >simply changing some wires. > >there are also quite a few other schemes out there... > >-jon > > >-- -------------------------------------------------------------- >To subscribe: [EMAIL PROTECTED] >To unsubscribe: [EMAIL PROTECTED] >READ THE FAQ!!!! <http://java.apache.org/faq/> >Archives and Other: <http://java.apache.org/main/mail.html/> >Problems?: [EMAIL PROTECTED] > -- -------------------------------------------------------------- To subscribe: [EMAIL PROTECTED] To unsubscribe: [EMAIL PROTECTED] READ THE FAQ!!!! <http://java.apache.org/faq/> Archives and Other: <http://java.apache.org/main/mail.html/> Problems?: [EMAIL PROTECTED]
