Hello, I''m setting up a server running Xen 4.3.1 on Gentoo but I am running into a weird issue. My machine has 64GB of RAM total. I''m trying to set dom0''s memory but no matter what I do it seems that the memory available to dom0 decreases when a VM is started. After a while, the system locks up; it responds to ping requests and shows the login prompt (on which you can enter a username, but the password input never appears) and that''s it. When we managed to get a dmesg, it showed that the system ran out of memory. I have the following options on the kernel line for xen: (XEN) Command line: placeholder dom0_mem=12288M,max:12288M dom0_max_vcpus=4 And I have the following options on the kernel line for dom0: placeholder root=ZFS=tank/dom0 ro apparmor=1 security=apparmor After starting a few test VMs (about 40), xm and xl report different values with regards to the memory available to the dom0: prometheus ~ # xm list Name ID Mem VCPUs State Time(s) Domain-0 0 12288 4 r----- 1277.6 prometheus ~ # xl list Name ID Mem VCPUs State Time(s) Domain-0 0 12040 4 r----- 1279.1 /etc/xen/xl.conf is at its default value, but setting it to off has no effect either: #autoballoon="auto" and I have set the following options in /etc/xen/xend-config.sxp: (dom0-min-mem 12582912) (enable-dom0-ballooning no) The values in /proc/meminfo do not change: prometheus xen # cat /proc/meminfo MemTotal: 12233120 kB MemFree: 2055792 kB Buffers: 2892 kB Cached: 250984 kB I have been banging my head on my desk for a few days about this. Any help would be appreciated. Thank you so much, Philippe
Roger Pau Monné
2013-Dec-13 11:20 UTC
Re: Xen 4.3.1 ignoring dom0_mem command line parameter?
On 13/12/13 01:44, Philippe Gagnon wrote:> Hello, > > I''m setting up a server running Xen 4.3.1 on Gentoo but I am running > into a weird issue. My machine has 64GB of RAM total. I''m trying to > set dom0''s memory but no matter what I do it seems that the memory > available to dom0 decreases when a VM is started. After a while, the > system locks up; it responds to ping requests and shows the login > prompt (on which you can enter a username, but the password input > never appears) and that''s it. When we managed to get a dmesg, it > showed that the system ran out of memory. > > I have the following options on the kernel line for xen: > > (XEN) Command line: placeholder dom0_mem=12288M,max:12288M dom0_max_vcpus=4 > > And I have the following options on the kernel line for dom0: > > placeholder root=ZFS=tank/dom0 ro apparmor=1 security=apparmor > > After starting a few test VMs (about 40), xm and xl report different > values with regards to the memory available to the dom0: > > prometheus ~ # xm list > Name ID Mem VCPUs State Time(s) > Domain-0 0 12288 4 r----- 1277.6 > > prometheus ~ # xl list > Name ID Mem VCPUs State Time(s) > Domain-0 0 12040 4 r----- 1279.1Hello, It seems that you are running both xl and xend at the same time, which is not recommended and is known to cause trouble. How do you launch your VMs?> /etc/xen/xl.conf is at its default value, but setting it to off has no > effect either: > #autoballoon="auto"Try setting it to "off", don''t start xend and create your VMs using xl only.