On 10/01/14 12:17, Johnny Hughes wrote: > On 01/08/2014 08:05 AM, David Vrabel wrote: >> On 08/01/14 13:59, Chris Elliott wrote: >>> At the moment we are using dom0_mem=3G,max:3G for example (where >>> dom0 mem and max values are the same). So we just need to allow a slightly >>> higher max value to leave some ballooned pages? >> Yes. >> >>> The Xen4centos documentation also says to use the same value for >>> dom0_mem and max. >> That should be updated with the workaround. >> >> David > > For completeness on this issue, here are the current kernel settings for > all XEN kernel variables: > [...] > > As can be seen, CONFIG_XEN_SELFBALLOONING is not set ... is this a > problem? (That option was decided during the beginning of the > Xen4CentOS process and I'm not sure if it is still valid). XEN_SELFBALLOONING enables automatic adjustment of the guest's own target based on memory usage. I don't think this a good idea, especially for a dom0. > If the kernel config option is still correct and if the Xen4CentOS Docs > need changing then I will make that happen. Thanks. I would suggest that approx. 16 MB per VM is a reasonable amount of pre-ballooned memory. e.g., dom0_mem=3G,max:4G would allow for approx. 64 VMs. David