Re: Advise on Web topology on System i -- WEB400

Jorge,

We've had a System i/iSeries/AS/400 publically available since late 1998. What has worked well for us is to put the web apps themselves on the exposed server and keep more sensitive stuff (like what you'd expect in your typical ERP system) on a separate server with a firewall in between. We do also keep fairly static and some transactional data (basically stuff related to online ordering) on the exposed server since performance is better accessing data locally than remotely (on a fast network, this really isn't much of an issue). Our apps are a mixture of RPG CGI, Net.Data, and Java running in WebSphere 5.1 Express.

We've also been on a variety of hardware and the only system we've really had performance problems with was the 50S we started with. We were on a 720 after that and we moved off of it primarily due to limitations with the amount of memory it could handle (1GB). We recently moved from a single processor 840 partition (circa 2001) to a single virtual processor 570 partition and we really only noticed a performance improvement on stuff that was disk I/O intensive. The processor is for sure much, much faster but the only big difference that made was in WebSphere startup (startup for 3 instances went from 10 minutes to 3 during IPL). Our apps are just not that CPU intensive.

Having enough memory does make a huge difference in performance and it is very easy to tell when that is a problem because of the excellent built in tools IBM provides. We have plenty of Windows and Solaris systems in our web farm (around 1000 servers total) and it amazes me on how much guessing it takes to figure out performance problems. The database monitoring tools are also much better than what I've seen for either Oracle or MS SQL Server.

I would not hesitate to run everything (or at least as much as the auditors will let you) on one System i. It was designed for mixed workloads (particularly I/O intensive ones) so unlike other systems, it is not a performance problem to run the web, app, and database tiers on the same server. One of the other big benefits you get is excellent hardware resiliency. Dead disks are usually handled well by everything but we've also had bad memory and our 50S lost its primary system bus once. These things did hurt performance some but the hardware just kept chugging along without any downtime.

BTW, we also have a separate System i (internal only and also a single processor partition that went from an 840 to a 570) that runs the credit card software that is used by our ERP system and various web sites, tax software, and a handful of other web services. That server has sent out 18TB of data (just over 4 million requests so they mostly return a lot of data) in the past 38 days. Average response time (excluding the credit card stuff which takes a few seconds due to external systems it talks to) is .36 seconds and CPU utilization is typically well under 10%.

Matt

-----Original Message-----
From: web400-bounces@xxxxxxxxxxxx [mailto:web400-bounces@xxxxxxxxxxxx] On Behalf Of Jorge Merino
Sent: Saturday, February 07, 2009 4:56 PM
To: web400@xxxxxxxxxxxx
Subject: [WEB400] Advise on Web topology on System i

Hi all.

I would like some advise from your experience serving web pages from the System I, let me me put some context:

For about a decade, we have been hosting and running web applications, dynamic custom web sites and just few static web sites; we used Linux servers and to balance the sites usage we had Back-end + Database + Archiving in one single server or in different servers, 95% of our development was done in PHP+MySQL.

In the other hand, System I related, we only have couple of low-usage web enabled programs that reads and provide data from our Legacy application on System i, we web-enabled those programs several years ago using PHP+MySQL to serve the Front-end, and for the back-end we built some C+Java tools that called any RPG program, that is the best we could do several years ago.

We are in the process on learn and prototyping with EGL, of course getting involved with RDi and V6R1 to use Websphere and so on.

We are having some problems to make WAS 70 to work, we are already talking with the IBM support to see what is going on, I expect to have it working pretty soon.

After this long reading, here are the question guys, is it a good idea to keep the System I to serve back-end as well as front-end? How the performance will be affected? How many shops out there have their System i serving web pages and the back-end without issues? have you had to have different machines serving User Interface, Bussiness Logic, Database, Archiving?.

Your thoughts will be highly appreciated, I want to get good performance for our 5250 users plus our Web users as well.

Thank you.

Jorge Merino