C[omp]ute

From: "andrew cooke" <andrew@...>

Date: Mon, 14 Jul 2008 15:56:30 -0400 (CLT)

This is taken from an email I wrote at work.  Responses from co-workers
suggested that VmWare would probably have been a better bet...


There's some software called Xen - http://www.xen.org/ - that somehow lets
you run several different OSes on a single machine.  We have been trying
to test [work stuff] with Oracle, so I thought I would install Solaris on
Xen (and then install Oracle on that to run the tests).

On the face of it, Xen appears to be pretty cool.  I eventually ended up
with a window on my (Linux) screen that contained a Solaris desktop (just
like a remote desktop).  And I didn't need to do any messing around with
dual booting to do it - the Solaris was installed off an ISO image sitting
on my Linux disk.

However, there were also a lot of problems.  Some because I'm not as smart
as I should be, and some because this seems to be rather new technology.
I should mention that I am using OpenSuse 11.0 and some of these may be
specific to that OS (on the other hand, Suse/Novell seems to have put
quite a bit of effort into packaging Xen into some "wizards" in the Yast
system that Suse uses for system management, so it's possible things are
actually worse on other Linuxes).

- The current Nvidia driver will not load.  So you need to downgrade to
the "legacy" drivers if you have an Nvidia graphics card.  This seems to
be a known Linux-wide problem.  As a consequence I have a low-res
(800x600!?) "VESA" screen (this might be improvable - it was enough hassle
to just get something that worked that I haven't touched it since).

- Nothing seems to be well documented.  I was *very* lucky in finding some
helpful people on IRC (Sun has a solaris-xen channel).  There are two ways
of running Xen (Full and Para-Virtual, whatever that means).  I gather PV
is better (faster?), but I couldn't get that to work at all.  With help I
got "Full" working with a specific Solaris build (NOT the one you get if
you follow the OpenSolaris "download" link - apparently the ISO image
needs to be specially tuned for Xen).

- To get this working, Linux itself also has to run on Xen.  This was
completely automated by Suse, and worked (apart from the Nvidia driver
issues).  But I imagine it might be tricky to get working otherwise (it
involved modifying the boot process - I need to reboot into the Xen
version; when I said dual booting wasn't necessary I meant not for the
Solaris part).

- Although I got Solaris running, I can't restart it!  The program to
restart images is crashing for me (I have a file on my Linux disk that, as
far as I understand things, is a disk image with Solaris installed, but I
cannot "boot" that disk).  I assume this is a known bug that will be fixed
ASAP, but it made the whole exercise pointless.

- The Solaris install did not include a connection to the net.   This
seems to be a known issue and Google turns up some possible solutions. 
However, in my case since the Linux machine I am using is also the DNS and
DHCP server for the local network, I am not sure how things would have
worked.

- I was particularly frustrated because after all that I found that Oracle
didn't support Solaris on x86 anyway - but that turns out to be just for
the latest release.  10g is supported.

Andrew