[Discuss] Using raw host hard disk in virtual client

[kentborg at borg.org (Kent Borg)]

Quite awhile ago I set up Linux clients on a Linux host, and looking 
for greater disk performance I gave the clients disk partitions 
directly.  I do not know if it made things faster, but I do know that 
it makes things a pain in general.  File systems are nice, they offer 
lots of features.

Unless one gets very bleeding edge and starts to break the virtual-
model (and heading para-virtual, a la Xen), I think one is stuck with 
double data copies for IO from VMs to disk.  But at least on a Linux 
host, I think the result can be very efficient.  Google for suggestions 
of what host file system to choose these days, etc.  (Disks and CPUs 
are getting dang fast these days, so double copies aren't so bad, but 
for if you really need performance, run on real hardware.)

And I would recommend a Linux host, and I think there are good 
technical reasons for that, but this is also a Unix/Linux mailing list, 
so one should expect us to say so.

I have been pretty happy with my Linux hosting Linux home server.  It 
is getting very long in the tooth and needs replacing, and I was only 
doing software Qemu, but it does work pretty well.  I climbed out on an 
early limb, but it worked.

-kb