[CentOS] is Intel VT-d "really" necessary?

Alexander Dalloz ad+lists at uni-x.org
Wed Sep 15 07:28:34 EDT 2010

> So, if VT-d really necessary?
> We mainly host XEN virtual machine for the hosting industry, i.e. we
> don't need / use graphics rendering inside VM's, or need DAS on the
> VM's, etc.

> Kind Regards
> Rudi Ahlers
> SoftDux

VT-d is not a necessity in general. It all depends on the kind of
virtualization you run. If you run only paravirtualized guests on Xen,
then there is not any need for VT-d (see [1]). If you fully virtualize for
instance Windows guests, then specific systems may profit i.e. from a
reserved network card by better network I/O.

Whether VT-d is useful to have may too depend on whether pricing for the
customer can be adjusted when providing such an extra feature.

>From own experience I concur that often with most modern x86 architecture
systems the I/O (network and storage) is the bottleneck in the area of

Just curious, do you really run virtualization for hosting on systems with
uni-processor design? I mean not choosing professional dual quad- or
hexa-core processor systems with Nehalem / Westmere Xeon CPUs or their AMD
Opteron counterpart?



[1] http://wiki.xensource.com/xenwiki/VTdHowTo

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