From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: Xen max supported memory per guest VM? Date: Mon, 16 Aug 2010 10:04:30 +0100 Message-ID: <4C691B3E020000780000FFCF@vpn.id2.novell.com> References: <20100814184248.GW2804@reaktio.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser , pasik@iki.fi Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org >>> On 14.08.10 at 23:18, Keir Fraser wrote: > On 14/08/2010 19:42, "Pasi K=C3=A4rkk=C3=A4inen" wrote: >=20 >> Hello, >>=20 >> In http://wiki.xensource.com/xenwiki/Xen4.0 we mention the following: >> "Better performance and scalability: 128 vcpus per guest, 1 TB of RAM = per >> host, 128 physical CPUs per host (as a default, can be compile-time in= creased >> to lots more)." >>=20 >> But what's the max supported amount of memory for a (64bit) guest? >=20 > Allocating the whole 1TB should work. It's unlikely to have been tested > though. Not everything will work with more than 512G: Anything that wants to access the guest's pfn_to_mfn_frame_list_list won't work, as there's no specification of how more than a page worth of these top level pointers should be expressed. Affected would be (afaict) save/ restore/migrate, kexec, and dumping of a crashed guest. Jan