Forgive me if I sent this twice, I think I hit the "send" button by
mistake.
--- Bj�rn Tore Svinningen <bt@erter.org> wrote:> I''ve seen your post on xen''s forum about running Xen
ontop of openssi.
>
> Have you got''en any further on this idea ? Had the same idea
myselves,
> but it seems all posts I find end nowhere.
Hm, I thought this question was answered.
No, you cannot because Xen is a hypervisor. As I understand it (in my limited
knowledge), a
hypervisor is a special kernel that sits between the hardware and all OSes, even
the "host" OS
(called Domain0 in Xen). The OpenSSI kernel cannot be placed underneath that --
it appears to be
an engineering impossibility. A hypervisor *must* talk directly to the
hardware; that''s what
makes it so fast.
As an alternative, you can do it the other way around; you can run OpenSSI on
top of Xen:
http://openssi.org/cgi-bin/view?page=docs2/1.9/debian/xen-howto.txt
I have begun to explore using Heartbeat+DRBD instead. Install Xen, install DRBD
into Dom0,
synchronize your DomUs on the DRBD partition, install Heartbeat, create another
node like the
first, use a script to stop/start the DomUs during a failover. Refer to
Linux-HA.org or the
xen-users archives for more details.
This is active/passive highly availablity. If you run DomUs on both nodes and
create two DRBD
partitions (one for each node) you can make effective use of your hardware and
get active/active
high availability, which is gives you crude load balancing. More like load
levelling, but good
enough for me. I would prefer not to have a "hot standby" wasting CPU
cycles; I would rather put
both nodes to work.
Of course if you really require true load balancing you can also run something
like LVS
(LinuxVirtualServer.org) as a front-end to your many Xen DomUs.
Heartbeat+DRBD+Xen scales out VERY WELL; if you need more processing power or
RAM, add another
pair of Heartbeat+DRBD+Xen hosts and migrate the existing DomUs to that.
Virtualization software
such as Xen makes moving servers around to different hosts VERY simple.
I think you''ll find that Heartbeat+DRBD+Xen is a great alternative to
running Xen on top of OpenSSI.
CD
Are you good enough?
TenThousandDollarOffer.com
_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users
