Hi,
I''m trying to figure out what the maximum amount of memory that can
be assigned to a domain is. I created a domain with a ludicrous
amount of memory and then tried to start it up, and got the
following error:
Error: I need 9999360 KiB, but dom0_min_mem is 200704 and shrinking
to 200704 KiB would leave only 7001948 KiB free.
I am wondering: where did the value 7001948 come from. Here is the
output of free on Dom-0:
total used free shared buffers cached
Mem: 1959936 1722756 237180 0 20680 1306968
-/+ buffers/cache: 395108 1564828
Swap: 4200988 744 4200244
The box has 2 GB (usually 2065264 kB) of ram (so 105328 kB already
seems to be missing). However, if I add up total memory + total swap
I still get only 6266252 kB free, and this is not even counting what
Xen has already reserved...
--Igor
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http://lists.xensource.com/xen-users
Nevermind, sort of,
This is actually an 8GB box. The problem appears to be that whenever
a domain is created, the amount of memory it''s using is deducted
from total memory and this amount is never restored, even after the
domain goes away:
xen1:~# free -m
total used free shared buffers cached
Mem: 7029 335 6693 0 6 35
-/+ buffers/cache: 293 6735
Swap: 4102 0 4102
xen1:~# free -m
total used free shared buffers cached
Mem: 3031 517 2513 0 7 211
-/+ buffers/cache: 297 2733
Swap: 4102 0 4102
This is Xen 3.2 on Debian Lenny. Here is my ''xm info'' --
anyone else
notice a similar problem?
xen1:~# xm info
host : xen1.mydomain.com
release : 2.6.26-2-xen-amd64
version : #1 SMP Wed Mar 10 00:29:48 UTC 2010
machine : x86_64
nr_cpus : 4
nr_nodes : 1
cores_per_socket : 4
threads_per_core : 1
cpu_mhz : 2327
hw_caps :
bfebfbff:20100800:00000000:00000140:0408e39d:00000000:00000001
total_memory : 8190
free_memory : 2234
node_to_cpu : node0:0-3
xen_major : 3
xen_minor : 2
xen_extra : -1
xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset : unavailable
cc_compiler : gcc version 4.3.1 (Debian 4.3.1-2)
cc_compile_by : waldi
cc_compile_domain : debian.org
cc_compile_date : Sat Jun 28 09:32:18 UTC 2008
xend_config_format : 4
--Igor
On Mon, Aug 02, 2010 at 09:25:34PM -0500, Igor Serebryany
wrote:> Hi,
>
> I''m trying to figure out what the maximum amount of memory that
can
> be assigned to a domain is. I created a domain with a ludicrous
> amount of memory and then tried to start it up, and got the
> following error:
>
> Error: I need 9999360 KiB, but dom0_min_mem is 200704 and shrinking
> to 200704 KiB would leave only 7001948 KiB free.
>
> I am wondering: where did the value 7001948 come from. Here is the
> output of free on Dom-0:
>
> total used free shared buffers cached
> Mem: 1959936 1722756 237180 0 20680 1306968
> -/+ buffers/cache: 395108 1564828
> Swap: 4200988 744 4200244
>
> The box has 2 GB (usually 2065264 kB) of ram (so 105328 kB already
> seems to be missing). However, if I add up total memory + total swap
> I still get only 6266252 kB free, and this is not even counting what
> Xen has already reserved...
>
> --Igor
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users
On Tue, Aug 3, 2010 at 10:01 AM, Igor Serebryany <igor47@moomers.org> wrote:> Nevermind, sort of, > > This is actually an 8GB box. The problem appears to be that whenever > a domain is created, the amount of memory it''s using is deducted > from total memory and this amount is never restored, even after the > domain goes away: > > xen1:~# free -mHint: Do NOT use "free". Use "xm list". If you want, you can also run "xm mem-set 0 ..." later to assign the unused memory back to dom0. Note that Xen is different from Vmware/virtualbox w.r.t. memory management. In Xen, you''re actually recommended to set dom0''s memory as small as it''ll ever be from the start. See http://wiki.xensource.com/xenwiki/XenBestPractices -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users