Xen for Human Beings

Erast Benson erast at gnusolaris.org
Wed Apr 26 19:40:50 BST 2006

> Erast Benson wrote:
>> But upcoming BrandZ[1] (Solaris 11 zones) will have additional syscall
>> layer which will allow to run OpenSolaris-based distribution like
>> NexentaOS[2] without *any* performance loss
> That's exceedingly unlikely. Every layer of abstraction that moves you
> away from bare metal necessarily introduces some performance degradation.

Please read what BrandZ is. There is no HW abstraction introduced. It only
introduces tiny software layer of syscall's abstraction. Look at  "3.4.
System Call Emulation" chapter at Design document[1].

>> and Linux-based distributions
>> with minimal performance loss (5-10%), which is way more efficient than
>> Xen/VMware/etc..
> Please read up on Xen's performance before making factually incorrect
> claims.

Nope. Xen technology badly loosing performance game to Zones, especially
when you start running 10-20 nodes. Zones are native. You could think of
Zone as of chroot environment with networking interface. Do you ever seen
noticable performance regression in chroot environment?

Having said that OpenSolaris's Xen port is ongoing effort[2] and I think
it is pretty usable already. And yes, Xen has its own benefits, like
hypervisor which overtime will benefit from Ring -1 of new generation
Intel/AMD CPU(s). But it will take time till all this hardware will become
common (yes motherboards, PCI bridges, etc needs to be changed too...)

[1] http://www.opensolaris.org/os/community/brandz/design
[2] http://www.opensolaris.org/os/community/xen

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