Hello,
VC 2.5 Update 3 w/ESX 3.5 Update 3 will monitor the health of the system. You can not alert on it however. As for bottlenecks VC does not have anything complex within in other than memory/CPU alerts. You could look at vFoglight, vKernel, as well as HPSIM, OpenManage, Directory, etc.
You can monitor things through MOM, Nagios, etc. It depends entirely on what you want to monitor. For 'bottlenecks' I would use VMware aware tools more than anything. general performance can be any number of tools.
Best regards,
Edward L. Haletky
VMware Communities User Moderator
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Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.
CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354
As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization
--
Edward L. Haletky
vExpert XIV: 2009-2023,
VMTN Community Moderator
vSphere Upgrade Saga: https://www.astroarch.com/blogs
GitHub Repo: https://github.com/Texiwill