Hi, We went for Esxi, with Vmware essentials, cost about £300 for 3 hosts managed via vcenter, so far so good most vm's are CentOS 5.x Running NFS shared storage on RHEL Regards Keith On 3 Jul 2010, at 04:52, Emmanuel Noobadmin <centos.admin at gmail.com> wrote: > Which of these would be the recommended virtualization platform for > mainly CentOS guest on CentOS host for running a virtualized mail > server? From what I've read, objectively it seems that VMWare's still > the way to go although I would had like to go with Xen or KVM just as > a matter of subjective preference. > > > VMWare's offering seems to have the best support and tools, plus > likely the most matured of the options. Also given their market > dominance, unlikely to just up and die in the near future. > > Xen would had been a possible option except Redhat appears to be > focusing on KVM as their virtualization platform of choice to compete > with VMWare and Citrix. So maybe Xen support will be killed shortly. > Plus the modified xen kernel apparently causes conflict with certain > software, at least based on previous incidents where I'd been advised > not to use the CentOS xen kernel if not using xen virtualization. > > > KVM would be ideal since it's opensource and would be supported in > CentOS as far as can be reasonably foreseen. However, looking at > available resources, it seems to have these key disadvantages > > 1. Poorer performance under load. > http://wiki.xensource.com/xenwiki/Open_Topics_For_Discussion?action=AttachFile&do=get&target=Quantitative+Comparison+of+Xen+and+KVM.pdf > This 2008 XenSummit paper indicates that it dies on heavy network load > as well as when there are more than a few VM doing heavy processing at > the same time. But that's two years ago and they weren't using > paravirtual drivers it seems. > > http://vmstudy.blogspot.com/2010/04/network-performance-test-xenkvm-vt-d.html > This blog testing out Xen/KVM pretty recently. While the loads are > not as drastic and neither the difference, it still shows that KVM > does lag behind by about 10%. > > This is a concern since I plan to put storage on the network and the > most heavy load the client has is basically the email server due to > the volume plus inline antivirus and anti-spam scanning to be done on > those emails. Admittedly, they won't be seeing as much emails as say a > webhost but most of their emails come with relatively large > attachments. > > > 2. Security > Some sites point out that KVM VM runs in userspace as threads. So a > compromised guest OS would then give intruder access to the system as > well as other VMs. > > Should I really be concerned or are these worries only for extreme > situations and that KVM is viable for normal production situations? > Are there other things I should be aware of? > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos