Re: Xen2 vs Xen3: features and stability?

[Luke Crawford <lsc%prgmr.com@localhost>]

Hmm.   I've mostly moved off of my NetBSD 3 (xen2) Dom0s because while 
once up, they are rock-solid, the xend daemon doesn't seem so stable; 
after adding 10 or 12 DomUs, the system does not allow me to startup or 
shutdown any more guests.  Also, support for linux 2.6 DomU kernels is a 
requirement in my environment.

That said, the difference in uptime between my Linux Xen3 Dom0s and my 
rock-solid NetBSD Xen2 Dom0 is rather shocking.

linux/Xen3:
lsc@auburn:~$ uptime
 10:12:38 up 20 days, 11:02,  7 users,  load average: 0.00, 0.02, 0.00

NetBSD/Xen2:
137: {1} uptime
10:00AM  up 121 days, 19:41, 5 users, load averages: 5.56, 4.34, 4.09

137: {2} uname -a
NetBSD 137 3.0.1 NetBSD 3.0.1 (amy-XEN0) #1: Wed Jul 12 02:33:02 PDT 2006 
lsc@:/usr/obj/sys/arch/i386/compile/amy-XEN0 i386

(The NetBSD box is the only one that meets any kind of reasonable SLA)

so yes, I am strongly considering moving to NetBSD4; the big problem with 
Xen3 is that it seems to still be something of a moving target (changes 
were made between 3.0.2-2 and 3.0.3 that broke NetBSD and FreeBSD DomU
support... NetBSD support is fixed now in -current and 4.0)

Of course, the other option is to put the effort into figuring out what's 
wrong with xen2-  at least then the specification isn't going to move out 
from under you;  there is significant demand for stable NetBSD/FreeBSD 
virtual servers.


On Wed, 22 Nov 2006, Johan Ihren wrote:
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> Hi,
>
> I've been running xen2 with great success for quite some time but I realize 
> its days are numbered. So when evaluating making the leap for xen3 I notice
>
> a) that I haven't found a comparision between the two anywhere. There are 
> bits here and there, like SMP domU's requiring xen3 and PCI access AFAIK 
> requiring xen2, but no comprehensive summary. If there is such a document 
> anywhere I'd much appreciate a pointer (and yes, I realize that a 
> Linux-centric document is likely to point at features not yet available for 
> NetBSD, and that's fine too, I can sort through that).
>
> b) what's the general feeling as to production worthiness of the xen3 stuff? 
> As stable as xen2 (which is working just great for me, and I use it for a 
> number of dom0's and dozens of domU's of different shapes and forms)?
>
> In general, as I don't need SMP at all, my gut feeling is that there's no 
> real rush to change...
>
> Regards,
>
> Johan
>
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