[opensuse-virtual] big differences in dom0 memory
I have two xen hosts - host1 is 32bit, 16Gb RAM, running 12.1+updates, kernel 3.1.9-1.4-xen. host2 is 64bit, 32Gb RAM, also 12.1+updates, kernel 3.3.0-2-xen. dom0 on host1 boots fine in 256Mb, but for host2 I need 512M. It's not a problem as such, but I'm curious as to why? I've also noticed that the virtual footprints of a few processes are significantly different from host1 to host2: Host2: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2769 root 20 0 705m 20m 1508 S 0 4.1 0:02.94 xend 2768 root 20 0 123m 12m 784 S 0 2.5 0:00.00 xend 2770 root 20 0 181m 7224 7052 S 0 1.4 0:00.31 blktapctrl 1 root 20 0 37180 4160 1916 S 0 0.8 0:00.89 systemd 2471 root 20 0 4094m 3848 2788 S 0 0.8 0:00.11 console-kit-dae 2543 root 20 0 184m 3052 2516 S 0 0.6 0:00.08 polkitd 882 root 20 0 315m 1456 1032 S 0 0.3 0:00.13 rsyslogd Host1: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 5023 root 20 0 71260 10m 1644 S 0 4.1 0:00.90 xend 5022 root 20 0 13952 7788 836 S 0 2.9 0:00.00 xend 2066 root 20 0 90160 3292 2644 S 0 1.2 0:00.06 console-kit-dae 2133 root 20 0 24304 2716 2328 S 0 1.0 0:00.60 polkitd 1 root 20 0 5148 2548 1856 S 0 0.9 0:00.62 systemd 735 root 20 0 40116 1260 948 S 0 0.5 0:00.10 rsyslogd For instance, xend on host2 appears to have a virtual footprint of more than 10 times that of xend on host1. Is this is really just due to 32 vs 64bit architecture? -- Per Jessen, Zürich (16.4°C) -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
On 30.04.12 at 13:21, Per Jessen <per@opensuse.org> wrote: I have two xen hosts -
host1 is 32bit, 16Gb RAM, running 12.1+updates, kernel 3.1.9-1.4-xen.
Hardly - there's no (supported) 32-bit Xen on 12.1.
host2 is 64bit, 32Gb RAM, also 12.1+updates, kernel 3.3.0-2-xen.
dom0 on host1 boots fine in 256Mb, but for host2 I need 512M. It's not a problem as such, but I'm curious as to why?
How can we know or even guess, when you neither tell us anything about the differences of the hosts beyond their bitness, nor describe (or even better provide hard data) in what way it fails with less than 512Mb. That said, I don't really see the point in this small a host - how would you expect any guests to run there (which after all is what you'd want to use Xen for)?
I've also noticed that the virtual footprints of a few processes are significantly different from host1 to host2:
Host2:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2769 root 20 0 705m 20m 1508 S 0 4.1 0:02.94 xend 2768 root 20 0 123m 12m 784 S 0 2.5 0:00.00 xend 2770 root 20 0 181m 7224 7052 S 0 1.4 0:00.31 blktapctrl 1 root 20 0 37180 4160 1916 S 0 0.8 0:00.89 systemd 2471 root 20 0 4094m 3848 2788 S 0 0.8 0:00.11 console-kit-dae 2543 root 20 0 184m 3052 2516 S 0 0.6 0:00.08 polkitd 882 root 20 0 315m 1456 1032 S 0 0.3 0:00.13 rsyslogd
Host1:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 5023 root 20 0 71260 10m 1644 S 0 4.1 0:00.90 xend 5022 root 20 0 13952 7788 836 S 0 2.9 0:00.00 xend 2066 root 20 0 90160 3292 2644 S 0 1.2 0:00.06 console-kit-dae 2133 root 20 0 24304 2716 2328 S 0 1.0 0:00.60 polkitd 1 root 20 0 5148 2548 1856 S 0 0.9 0:00.62 systemd 735 root 20 0 40116 1260 948 S 0 0.5 0:00.10 rsyslogd
For instance, xend on host2 appears to have a virtual footprint of more than 10 times that of xend on host1. Is this is really just due to 32 vs 64bit architecture?
Presumably not directly, but given the list of processes above I don't see the direct relation to Xen - apart from xend, all others aren't Xen specific, yet show similar patterns. For xend, given that it's a Python script, looking at Python's footprint in general would probably get you much further. Jan -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
Jan Beulich wrote:
On 30.04.12 at 13:21, Per Jessen <per@opensuse.org> wrote: I have two xen hosts -
host1 is 32bit, 16Gb RAM, running 12.1+updates, kernel 3.1.9-1.4-xen.
Hardly - there's no (supported) 32-bit Xen on 12.1.
I guess I must have built it from source.
host2 is 64bit, 32Gb RAM, also 12.1+updates, kernel 3.3.0-2-xen.
dom0 on host1 boots fine in 256Mb, but for host2 I need 512M. It's not a problem as such, but I'm curious as to why?
How can we know or even guess, when you neither tell us anything about the differences of the hosts beyond their bitness, nor describe (or even better provide hard data) in what way it fails with less than 512Mb.
The hosts are virtually the same - both quad Intel Xeon, one is 4x2.8GHz, the newer one is 4x3.0GHz. When I started host2 with dom0_mem=256Mb, I saw lots of oom messages and it ended with a kernel panic.
That said, I don't really see the point in this small a host - how would you expect any guests to run there (which after all is what you'd want to use Xen for)?
I must have misunderstood something - what is the typical or recommended size for dom0?
I've also noticed that the virtual footprints of a few processes are significantly different from host1 to host2: [snip] For instance, xend on host2 appears to have a virtual footprint of more than 10 times that of xend on host1. Is this is really just due to 32 vs 64bit architecture?
Presumably not directly, but given the list of processes above I don't see the direct relation to Xen - apart from xend, all others aren't Xen specific, yet show similar patterns. For xend, given that it's a Python script, looking at Python's footprint in general would probably get you much further.
Thanks, I was thinking that too (after I'd hit send). -- Per Jessen, Zürich (21.8°C) -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
On 30.04.12 at 15:11, Per Jessen <per@opensuse.org> wrote: I must have misunderstood something - what is the typical or recommended size for dom0?
This is obviously load dependent, but as a first guess we typically suggest 1 to 2 Gb. Jan -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
participants (2)
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Jan Beulich -
Per Jessen