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Re: Linux 3.2 in wheezy

On 02/03/2012 01:55 AM, Vincent Bernat wrote:
> With vservers and  OpenVZ you can run each service  in its own container
> with a small  memory footprint. With Xen/KVM, you  will need to allocate
> at least 128 MB for each container.
NO ! The limit isn't that great.

With Etch, 48 MB was enough. With Lenny, 64 MB was enough.
With Squeeze, 96 MB is enough (the minimum is between 64 and
96 MB, I didn't care investigating). And with 96 MB, you can already
run a DNS server, OpenVPN, or a (very basic) mail server. The issue
though, might be with things like locales generation or other RAM
intensive stuff in Debian, which may need a bit more RAM to run
smoothly. But in such case, you'll have the issue with both KVM/XEN
and containers, so it doesn't really apply as a point in the discussion

In fact, the main issue when booting a VM with a low RAM footprint,
is the size of the initrd, which over the years, is growing and growing,
which means that you need a large amount of RAM to even load it.

But if you customize a bit your initrd (which means, removing all
useless drivers), you can really use a lot less RAM.

So, ok, you need more RAM, but not as much as 128 MB.

That doesn't discard your argument of the RAM usage all together,
it's really truth that a container will use less RAM. But please, be
reasonable when trying to make your point, and keep it with
facts that you have checked by yourself.


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