Monitoring Multiple Servers (100+)

Clarifications

First of all you'll have to determine what you, or your company, wants monitored. Hardware failures, server up/down, service status, eventlogs. Depending on these choices you can start picking a product. And it will of course also depend on the budget you have/get for it.

Are your servers a common vendor (HP, Dell etc)? If so, those vendors will have a tool for monitoring their hardware.
If you have a mixed environment, you could look at GFI Network Server Monitor. I have always like GFI products.
http://www.gfi.com/nsm/
I don't think you will really get any commerical software for that many systems for $1000 though. You are probably looking at around $2000 for GFI and most likely more for other providers.
Regards.

http://www.netiq.com/products/am/default.asp?WT.srch=1&kw=monitor%20multiple%20servers&gclid=CMet0dqqn5QCFRJ1ugod3Vk_tA
http://www.nimsoft.com/solutions/server-monitoring/index.php?sfid=70160000000HE8j&source=gge&cid=Server-Monitoring&group=General-Server-Monitor&_kk=server%20monitoring
http://manageengine.adventnet.com/products/opmanager/server-monitoring.html?gclid=COqCq8irn5QCFRJ3ugodNwz9tA
http://www.dirfile.com/freeware/powerful2.htm
http://barry.wordpress.com/2007/07/18/keeping-track-of-300-servers/
http://www.ibm.com/developerworks/websphere/library/techarticles/0304_polozoff/polozoff.html
http://www.5starshare.com/xSQL_Profiler-soft58760.html

Please post back if you have any more problems or questions.

http://www.woodstone.nu/salive
http://www.serverscheck.com
http://www.nagios.org

You will just need a server to put it on but it is free.
Takes a bit to set up but works well and should keep you within budget. As an added bonus, unlike other free softwares Nagios has pretty good support. It comes by way of the user community but I have found it to be more than useful with any issue I have had.

I will be reviewing and testing the software recommendation.

Regards

SolarWinds Server & Application Monitor, it makes it easy to monitor custom applications including component monitors for services, processes, ports, scripts, WMI performance counters, and scripts from 3rd party open source monitoring tools such as Nagios.

http://www.solarwinds.com/server-application-monitor.aspx