[Freedombox-discuss] [vserver] Re: [vserver] Re: A software architecture for?the FreedomBox

[Eugen Leitl]

----- Forwarded message from Gordan Bobic <gordan at bobich.net> -----

From: Gordan Bobic <gordan at bobich.net>
Date: Thu, 14 Apr 2011 10:36:53 +0100
To: vserver at list.linux-vserver.org
Subject: Re: [vserver] Re: [Freedombox-discuss] [vserver] Re: A software architecture
	for the FreedomBox
Reply-To: vserver at list.linux-vserver.org
User-Agent: Mozilla-Thunderbird 2.0.0.24 (X11/20100328)

Eugen Leitl wrote:

>>>>> One of the first things you have to do when building a
>>>>> system like the FreedomBox is figure out the software
>>>>> architecture. I have come up with an interesting
>>>>> architecture that is made of Linux Containers (Virtual
>>>> Using Linux vserver guests for service separation (jails on
>>>> steroids) is an excellent idea, actually.
>>> I find it interesting, but am sceptical: I believe each
>>> jail consume separate memory for their libraries - i.e.
>>> cannot benefit from shared libraries. So I worry about memory
>>> consumption.
>> mainly depends on the guest setup, assuming that the
>> guests use identical libraries and the on disk data
>> is properly unified, then both, the inode cache and
>> the page mappings will use the very same memory
>
> Vserver unification hasn't been something really solid in the past, often
> brokeni, at least in Debian.

I've only seen one instance of it being broken, and I posted about it on  
the list. It was on ext4 fs back before ext4 was actually deemed stable,  
and all the newer kernels since have worked just fine. I suspect you just 
had a duff kernel. Did you roll it yourself or did you use a pre-packaged 
one?

Here's a link to the thread on the subject from last year:
http://www.paul.sladen.org/vserver/archives/201010/0018.html

> Note that the vserver patch support in Debian will stop with wheezy. LXC
> might be a better choice in the long term.

Frankly, the only advantage LXC has is that it's in the mainline. Having  
argued a case for a hashify feature in it before, my impression that the  
chances of having it in LXC is effectively 0.

Here's a thread where I brought it up on the LXC list a while back:
http://www.mail-archive.com/lxc-users@lists.sourceforge.net/msg00433.html