Is there any way to make the xen kernel see more then 16GB of ram when its installed on a 32bit OS (either FC6 or FC7)? I tried FC7 64bit since it can see all the ram, however the only 32bit OS I was able to install successfully was windows XP. Every other distro (FC6, FC7, and CentOS 4.5 & 5.0) would freeze up at some point in the installation or bootup section. I have a machine with 28GB of ram and have a month to get it running. Marco Jorge
On Wed, Jun 27, 2007 at 05:00:13AM -0400, thewird wrote:> Is there any way to make the xen kernel see more then > 16GB of ram when its installed on a 32bit OS (either > FC6 or FC7)?No it is an architectural limitation of Xen that 32-bit is limited to a maximum of 16 GB, even with PAE.> I tried FC7 64bit since it can see all the ram, > however the only 32bit OS I was able to install > successfully was windows XP. Every other distro (FC6, > FC7, and CentOS 4.5 & 5.0) would freeze up at some > point in the installation or bootup section. > > I have a machine with 28GB of ram and have a month to > get it running.64-bit is the way to go. Try toggleing the ''acpi'' and ''apic'' settings for the HVM guests as this often helps with lockups. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
Daniel P. Berrange wrote:> On Wed, Jun 27, 2007 at 05:00:13AM -0400, thewird wrote: >> Is there any way to make the xen kernel see more then >> 16GB of ram when its installed on a 32bit OS (either >> FC6 or FC7)? > > No it is an architectural limitation of Xen that 32-bit is limited to > a maximum of 16 GB, even with PAE.Well, there is one from the dirty tricks department: Install 32bit fc7, pull 64bit xen kernel from the 64bit kernel-xen rpm, boot that with the 32bit linux kernel. Mixing 32bit and 64bit guests isn''t going to work for the time being (needs a kernel update). But with the 64bit hypervisor underneath the system should be able use all memory, even with 32bit guests only. cheers, Gerd
On Sat, Jun 30, 2007 at 01:59:34AM -0400, thewird wrote:> How do I do that with the new xml configuration files > for xen in Fedora 7? I tried <acpi>0</acpi> but when I > define it back into the database, it gets rid of my > change. I suspect I''m using the wrong syntax but > theres no documentation at all on the new xml format.Check out this http://libvirt.org/format.html In the section ''Fuly virtualized guests''. To turn it on try: <features> <acpi/> </features> Or to turn it off, just leave out the <acpi/> tag Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|