Re: Copy-on-write memory to allow many more xenU domains per machine

[Peri Hankey <mpah@thegreen.co.uk>]

I hadn't been thinking of the honeypot scenario myself, but of the plain 
old 'more virtual computers than you would have thought possible' scene. 
>From Ian's account of it there's less scope for that than I had imagined.

I can be heavy slow myself ('heavy' is apparently Glaswgian slang for 
'very' - think 'heavy light') - especially when immersed in the 
technical undergrowth.

Regards
Peri




Michael Vrable wrote:

>On Mon, Oct 25, 2004 at 01:12:22PM +0100, Peri Hankey wrote:
>  
>
>>Some time ago Michael Vrable talked about copy-on-write memory to enable 
>>large numbers of nearly identical machines to run on the same physical
>>hardware. Is this a feasible proposition? I asked a few days ago in the 
>>original thread, but no-one seems to have noticed. It seems to me that 
>>it would be a very significant feature to offer.
>>    
>>
>
>I'm still around, though a bit slow to respond.
>
>Ian mentioned that honeypots are one the scenarios where copy-on-write
>sharing of memory makes a lot of sense; that's the reason that I'm
>trying implement it.  I hope, of course, that if I do manage to get
>something working it would be useful in other scenarios as well.
>
>My current status: I've been working first on using shadow page tables
>to hide the actual machine addresses of pages from domains.  I'm only
>partway through doing that, and may yet go back and change how I'm
>approaching that (I'm still learning bits about how Xen works as I'm
>going through to modify the code; I'm also thinking now of changes that
>would be good to make copy-on-write easier later).  I'm trying to write
>up some of my design thoughts; if anyone here is interested or would
>like to offer comments, I can post that here.
>
>David mentioned implementing a clone() for VMs; that is something that
>I'd also like to try out.  (It should be possible to test that after
>only the first step of hiding machine addresses, before copy-on-write is
>implemented, though copy-on-write will make it efficient.)
>
>If someone else beats me to getting this implemented, I suppose I can't
>complain.  But if this is an area that isn't getting much current work,
>and I'm able to contribute (a hopefully clean implementation that others
>wouldn't mind using), that would be great.
>
>--Michael Vrable
>
>
>-------------------------------------------------------
>This SF.net email is sponsored by: IT Product Guide on ITManagersJournal
>Use IT products in your business? Tell us what you think of them. Give us
>Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more
>http://productguide.itmanagersjournal.com/guidepromo.tmpl
>_______________________________________________
>Xen-devel mailing list
>Xen-devel@lists.sourceforge.net
>https://lists.sourceforge.net/lists/listinfo/xen-devel
>
>
>  
>



-------------------------------------------------------
This SF.net email is sponsored by: IT Product Guide on ITManagersJournal
Use IT products in your business? Tell us what you think of them. Give us
Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more
http://productguide.itmanagersjournal.com/guidepromo.tmpl