Xen 3

[Kurt Granroth]

I hear what you're saying.  And, in fact, I do use VMWare to run a  
Windows session.  However, I disagree that VMWare is used primarily  
for cross-os work.  The vast majority of the time that I've used it  
was for other virtual Linux machines.  And the vast majority of the  
time that I've heard other people use it was for Linux work.  Really,  
if using Windows is the goal, then Win4Lin is much cheaper (unless  
you already have a license) and much faster than VMWare.

I think VMWare recognizes the Xen threat to their business as well.   
Why else would they all of a sudden start offering the VMWare Player  
for free?  Xen is still pretty immature (3.0 version notwithstanding)  
but the future is undeniably bright.

I agree the UML is currently a viable alternative to Xen.  I used to  
run my web/mail/proxy/file server inside of a UML session which was  
very handy.  However, UML has the singular disadvantage of being  
sooooo slooooooow.  It certainly wasn't bad for my use since a server  
for a single person isn't very resource intensive... but if you want  
to do anything more, forget it!  Xen, meanwhile, if with the TLS/NPTL  
hit is still with a few percent of the host system, performance-wise.

Anyway, I like 'em all.  Each of the emulator/simulator/hypervisor  
solutions has their own pluses and minuses and it's worth checking  
them all out for any specific need.

On Dec 8, 2005, at 9:44 AM, Dan Lund wrote:

> Thus, as I said, it's not an alternative to VMWare :)
> Sure, it's the same idea, in a limited scope and with far too many
> eccentricities to be seriously considered a viable alternative.
> If going linux-only, I'd consider Usermode Linux to be more of an
> alternative to VMWare.  I have a track record with that, and I know it
> works without my altering anything other than the kernel.
> However, most times when the name VMWare comes up, it means cross-os
> usage.  With that, there aren't many other options other than Qemu,
> Bochs, and Plex86.
>
> --Dan
>
> On 12/8/05, Kurt Granroth <plug-discuss at granroth.org> wrote:
>> Xen is most certainly an alternative to vmware.... depending on  
>> how you use
>> vmware.  At Ticketmaster, we do a lot of development on devel  
>> "clusters" made
>> up of a bunch of vmware esx servers running Linux as the client  
>> OS.  This
>> allows us to have only a few beefy boxes but (roughly) as many  
>> virtual
>> systems as we need.  Xen could work very well in this role.
>>
>> Now Xen does have some drawbacks compared to vmware.  Some of them  
>> are:
>> o Doesn't play well with NPTL/TLS without a performance hit.  This  
>> may require
>> modifying the host and client glibc... not always a pleasant task
>> o No capability for snapshots
>> o Missing most if not all of the "enterprise" management features  
>> of the
>> vmware server products
>> o Can't run Windows
>> o Installing a Linux OS that doesn't directly support Xen can be a  
>> pain
>>
>> The big advantages, of course, are that it's very fast, doesn't  
>> use as many
>> resources as vmware, and it's free.
>>
>> I base all this mostly on articles I've read on Xen as I've been  
>> following it
>> relatively closely for awhile.  I do have a Xen installation with  
>> SuSE/SuSE
>> (*very* easy to install) but haven't done more than just play  
>> around with it.
>>
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