Re: [Qemu-devel] default guest RAM size?

["Daniel P. Berrange" <berrange@redhat.com>]

On Thu, Mar 07, 2013 at 02:34:53AM +0800, Peter Maydell wrote:
> On 6 March 2013 11:59, Rob Landley <rob@landley.net> wrote:
> > On 03/05/2013 12:09:27 AM, Peter Maydell wrote:
> >> On 5 March 2013 14:07, 陳韋任 (Wei-Ren Chen) <chenwj@iis.sinica.edu.tw>
> >> wrote:
> >> > On Tue, Mar 05, 2013 at 01:40:38PM +0800, Peter Maydell wrote:
> >> >> On 5 March 2013 13:26, Michael Tokarev <mjt@tls.msk.ru> wrote:
> >> >> > For many years, qemu defaults to 128Mb of guest RAM size.
> >> >> > Today, this is just too small, and many OSes fails to boot
> >> >> > with this size, more, they fail to produce any reasonable
> >> >> > messages either (eg, windows7 just crashes at startup).
> >> >>
> >> >> If you make the default bigger then some boards will crash
> >> >> or behave weirdly because they try to map more RAM in than
> >> >> will fit into the space for RAM in their address maps.
> >> >
> >> >   So, 128Mb is still a good default? I am just wondering if those
> >> > boards with little memory still are major user of QEMU? :)
> >>
> >> They may not be major but they're still in the codebase. You
> >> can't just arbitrarily break them -- you need to propose
> >> a path forward that doesn't do that.
> >
> > 256 can be handled by most things.
> 
> I'm going to take a wild guess that Windows 7 doesn't do any
> better in 256MB than it does with 128 :-)

Indeed documented min requirements for Win7 are 2 GB on x86_64. In fact
very few modern OS accept anything as low as 256 MB. If you want adefault
that is suitable for anything mainstream then we're talking GB's not MB's.

Daniel
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