We are about to upgrade our servers. Currently we are using 2 x pSeries with zeus web server and WAS 5 app server. We experiense periods of extreme load with a couple of hundred thousand unique visitors per day at its peaks (we are selling cinema tickets and experienced extreme peaks on the release of for example Lord of the rings). We are now thinking of replasing or two pSeries (RS6000) with three or four xSeries (intel) running RedHat Linux. The main reason is the lack of aix competence but also a cost issue. Has anyone got some advice whether or not to switch from aix to linux. I have allways believed aix to be far superior to linux, but i am not that sure anymore.
What about FreeBSD 5.2. Now it supports AMD 64 Opteron systems.
Have you considered Opteron servers? Take a look at this link for some webserver benchmarks:
Linux on intel is definitely cheaper and more power per buck. We moved from solaris to linux and there were a number of factors that influenced our decision. The software we run on it is optimied for linux and the JVM was also too. This is a search application which is of high traffic.
We load balanced on two linux boxes and the performance gain we have seen is 40 to 60%.
Red hat has max heap size limitation of 1.7Gb actually 2.0 but JVM needs some space for native processes.
A lot of sofware incompatibilities. I suggest run a health check on each version of software you use, perl(?), app server(?), jvm, third party softwares?, we had a tough time deciding on which version of red hat to go with as some were to "end of life" soon.
Rest was smooth.
I'm sure that AIX can scale much better than Linux, but when you compare putting a couple of relatively cheap Linux boxes with dual CPUs and a load balancer in front with a big AIX computer you're talking completely different pricing. Unfortunately I can't give you a comparison between AIX and Linux, but we've run quite a lot of testing on our app between Solaris(Sparc)/Linux(Intel)/HP-UX(Risc) and so far Linux virtually runs when the others are walking. I'm not a Linux-will-save-the-world fan, I just find it to work really well and for me the Intel processors are much faster if you're just talking a pure web app with ejbs - no long running transactions etc. Hope this helps.
Linux is surpassing AIX more each day. I'm an AIX fan, but costs of the P-Series hardware has been increasingly pushing me towards Linux.
This article really puts things in perspective: