On Wed, Sep 15, 2010 at 1:28 PM, Alexander Dalloz <ad+lists at uni-x.org> wrote: > 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. ok, that's kinda what I thought as well. We don't use Windows VM's, but rather dedicated Windows servers if needed. > > 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 > virtualization. That's what I found as well so I want to concentrate on better I/O throughput. In general we don't saturate the 1GB NIC's. As soon as it gets to a certain threshold, we move some of the VM's to a new server instead. I guess I could look into dual / quad NIC bonding, but that would mean downtime on the server while the NIC's are installed. > > 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? > Generally we use systems with 8cores+, i.e. Quad Core with HT, or dual Quad Core with HT. But I want to see if I could use the money spend on those expensive CPU setups more wisely with RAM & I/O. > Regards > > Alexander > > [1] http://wiki.xensource.com/xenwiki/VTdHowTo > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > -- Kind Regards Rudi Ahlers SoftDux Website: http://www.SoftDux.com Technical Blog: http://Blog.SoftDux.com Office: 087 805 9573 Cell: 082 554 7532