Replying to myself: On Sun, Oct 23, 2011 at 5:51 PM, Peter Peltonen <peter.peltonen at gmail.com> wrote: > There is something fishy going around... I will now try to yum update > dom0 and domUs, set the dom0-min-mem to 2048M and reboot and see what > happens. After rebooting I seemed to have 2048M in dom0 regardless of how many domUs were running. But when trying to create the last domU, I was informed that xend was out of memory. At this time I still had something about 5G of real memory available for the last domU which I have configured to consume 4G of memory. I tweaked grub.conf and xend-config.sxp and set 4096M as the dom0 memory and rebooted again. I reduced the domU memory sizes accordingly and all domUs got created without errors. But the strange thing is again dom0 memory which has been reduced from 4096M to 2052M: [root at si ~]# cat /etc/xen/xend-config.sxp |grep dom0-min-mem # dom0-min-mem is the lowest permissible memory level (in MB) for dom0. (dom0-min-mem 4096) [root at si ~]# xl info |grep mem total_memory : 24567 free_memory : 5853 xen_commandline : dom0_mem=4096M dom0_max_vcpus=1 dom0_vcpus_pin [root at si ~]# xl list Name ID Mem VCPUs State Time(s) Domain-0 0 2052 1 r----- 265.6 xl top reports "(MEM)k" as "2101272" and "MAXMEM(k)" as "no limit". In CentOS5 with Xen3 I have been used to having the amount of memory in dom0 which I have specified. My Xen4 installation seems not to do this. If someone else is using the Xen4 packages from http://xenbits.xen.org/people/mayoung/EL6.xen I would be interested in hearing about your experiences? BR, Peter