I wrote about Zabbix Installation for Layman sometimes back and really recommended it
But now days, look like myself in deep troubles with the same. I am getting strange kind of problems in the well established setup of Zabbix, when no one has altered any kind of configuration that is really very very strange. May be my knowledge about this product is lesser; may be reason is just that I am unable to find any proper book over it; may be the manual itself is one of worse, one could come across. Reason might be any of them or all of them, but its getting really unstable for me. It works perfectly after installation for sometime but gets unstable soon as data grows. I am just finding one different thing in my environment that our servers run 9 AM-9PM, not 24 hours, but this should be the reason for any standard product.
List some of the issues I am facing with it, which are yet unexplained/ unresolved:
Problem 1: High Dependency on Local Time :- The first problem I faced with Zabbix was, its going completely out of tune once somehow local time of the server get altered by any means. I tried even network time, but just of no use. You are left to pray about this only. Its been an issue since long.
I really think that it should have been fixed till now, if you were offering this solution to corporate as along this ‘bug’ makes it completely unreliable.
Problem 2: Broken graphs later on as Data increases :- I am really not sure about this problem. I am getting many strange scenarios with it. The biggest Zabbix Server of mine was taking care of around 25-30 servers and this was going awry again and again. Like I am getting data in latest data tab correctly, I am getting data in 4 hours and 8 hours graphs correctly, but getting no graphs in 1 hour and 2 hours graphs, while its showing data but no lines on graph.
Searching through forums say that it might due to much data in MySQL tables and MySQL might be needed to be retuned. But I don’t think that such an application would not be able to handle a mere 2 dozen servers for even straight 7 days. No disk space issue (100 GB free), No Memory Issue (1 GB RAM), processor is Core 2 Duo. I am enabled house cleanup, have increased the memory limits, but still….
Problem 3: No support as I am unable to find any person, who knows this software a bit more. Look like most of the people using more worse NagiOS only. Professionals require contract for support and forums are not that useful as its not a simple piece of application and problems are of diverse nature… literally too many. Logs are confusing and most of the time not that much info even on setting it on debug mode.
My aim of this post is not to criticize Zabbix itself here, but its support is really poor and many things not that explained in forums and manuals. Much hard to find anyone, who knows it through.
Currently looking for someone, who might be dealing with Zabbix in his environment and could offer help out of the way. I want to invite all who know a thing or two about Zabbix to share the knowledge with me and same will be with myself.
Nitish Kumar 
why don't you try #zabbix on freenode irc network ?
of course, usual irc etiquette applies, like not being impatient, giving all required information etc :)