Re: [IMail Forum] IMAIL 6.03 How do I Config to load balance behind a Cisco 6509

[Sanford Whiteman]

You did not read my post -- perhaps you skimmed it.  There is no "true" load balancing -- this is a figment of your imagination.  Load balancing -- which is a concept only, not a trademark! -- is based on (a) distribution or replication of content and (b) content-sensitive or utilization-sensitive redirection.  I have used several market-leading hardware and software load balancers, and there are none that truly "poke" POP3 performance at the application layer (they will poke for HTTP, FTP, et al. responsiveness) as part of their LB algorithm.  You would thus be reduced to "best-guess" based on server utilization or basic round-robining.  Thus, the environment I described is the best way to use commercial LB front ends against an Imail server farm.  Yes, you *can* have just one exposed IP address -- this is the default behavior with HydraWEB, Radware, etc.    In addition, you are dead wrong about WLBS' resource footprint.  It is not resource-intensive and performs extremely well at load-balancing replicated content.   S.   P.S. If you don't like my answer, give a better one.  Your attack was OT, as my response was to Dean Zerbe's query and was fully appropriate to the question. -----Original Message----- From: Dave Koontz <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> Date: Tuesday, May 02, 2000 8:42 PM Subject: Re: [IMail Forum] IMAIL 6.03 How do I Config to load balance behind a Cisco 6509 I am sorry, but this does not sound at all like "Load Balancing". Why should you have to "Segment" your user base?  In a true Load Balancing server scheme, multiple servers would answer to the same IP Address - based on server load, and all would use the same exact user base on an external device available to each server.  It should be a 100% "automated" system - NOT partially manual.  All currently available servers play....equally!   Not just the which outgoing SMTP servers are active game, which does nothing for POP, HTTP, IMAP or other "user" access.   If you are counting on WLBS, you need to do some serious research --- it is a clustering solution at best, with tremendous overhead.  TRUE load balancing can be handled easily at the router level or with software such as Resonate's Central Command. ----- Original Message ----- From: Sanford Whiteman To: [EMAIL PROTECTED] Sent: Tuesday, May 02, 2000 6:45 PM Subject: Re: [IMail Forum] IMAIL 6.03 How do I Config to load balance behind a Cisco 6509 Local SMTP/POP3-wise, the Imail "Peer Server" function will help you accomplish this.  You set your Imail servers up to "overflow" to each other, after segmenting your user base across the servers (you can use a round-robin algorithm when creating the SQL statement that creates accounts).  You can even share the same SQL database if you want -- just use different tables.  This way, if a load-balanced request comes in for a given POP3 account that isn't actually hosted on the destination server, it will search the cluster and redirect the traffic.  Note that the TCP/IP traffic is still routed through the destination server (it doesn't actually get redirected, HTTP-style), but you save disk I/O and actual SMTP processing.   Remote SMTP-wise, you don't really need to do anything except point clients to the cluster address.  You may want to give each box the same primary hostname to avoid Reverse DNS issues.   Overall, it's partially manual and partially automated, but it works.   Sandy -----Original Message----- From: Zerbe, Dean <[EMAIL PROTECTED]> To: '[EMAIL PROTECTED]' <[EMAIL PROTECTED]> Date: Tuesday, May 02, 2000 6:14 PM Subject: [IMail Forum] IMAIL 6.03 How do I Config to load balance behind a Cisco 6509 My company is running a Cisco powered network. with 2 Cisco GSR's  those are connected to 2 6509 switches.  the Cisco 6509 has the ability to do load balance.  the hardware I am using allows 2 Ethernet ports to be connected for each server to theoretically do 200mbps full duplex.  this network is fully fault tolerant   Now the Question....   How should I configure IMAIL or should I bother?     My possible concept.     run 4 or more front end IMAIL servers load balanced from the Cisco 6509.  have those servers sync users by using a SQL 7.0 database.  have the directory structure point to a UNC  \\bigdiskserver\domainxyz.     then presto it all crashes because of open file issues? I don't know any ideas would help?  even other products you tell me   the SQL server and location for the file are in a Microsoft cluster server.   this is expected to hold 500,000  + accounts.