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RE: [Xen-users] xen 4.1 missing memory

To: "Yi, Shunli" <syi@xxxxxxxxxxxx>, "Fajar A. Nugraha" <list@xxxxxxxxx>
Subject: RE: [Xen-users] xen 4.1 missing memory
From: "Ian Tobin" <itobin@xxxxxxxxxxxxx>
Date: Thu, 18 Aug 2011 08:30:02 +0100
Cc: Xen User-List <xen-users@xxxxxxxxxxxxxxxxxxx>
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Thread-topic: [Xen-users] xen 4.1 missing memory
My config is a little different, here is what is currently set:-

# dom0-min-mem is the lowest permissible memory level (in MB) for dom0.
# This is a minimum both for auto-ballooning (as enabled by
# enable-dom0-ballooning below) and for xm mem-set when applied to dom0.
(dom0-min-mem 512)

# Whether to enable auto-ballooning of dom0 to allow domUs to be
created.
# If enable-dom0-ballooning = no, dom0 will never balloon out.
(enable-dom0-ballooning no)


Output of top

Cpu(s):  1.9%us,  5.8%sy,  0.0%ni, 91.5%id,  0.0%wa,  0.0%hi,  0.1%si,
0.7%st
Mem:    302000k total,   260088k used,    41912k free,     1020k buffers
Swap:  1501944k total,    41700k used,  1460244k free,    17460k cached



thanks




-----Original Message-----
From: Yi, Shunli [mailto:syi@xxxxxxxxxxxx] 
Sent: 18 August 2011 08:14
To: Ian Tobin; Fajar A. Nugraha
Cc: Xen User-List
Subject: RE: [Xen-users] xen 4.1 missing memory

Seems there is still enough memory.
So, suggest to disable the balloon driver, and have a try.
In /etc/xen/xend-config.sxp:
# Dom0 will balloon out when needed to free memory for domU.
# dom0-min-mem is the lowest memory level (in MB) dom0 will get down to.
# If dom0-min-mem=0, dom0 will never balloon out.
(dom0-min-mem 256)

Try set (dom0-min-mem 0)  to disable the balloon function.

Temporarily, set the Domain0 memory by "xm set-mem 0 512" if  you don't
want a Domain0 reboot.

-Shunli

-----Original Message-----
From: Ian Tobin [mailto:itobin@xxxxxxxxxxxxx]
Sent: Thursday, August 18, 2011 3:01 PM
To: Yi, Shunli; Fajar A. Nugraha
Cc: Xen User-List
Subject: RE: [Xen-users] xen 4.1 missing memory

Sure, some bits changed for privacy reasons

xm root@myhost:~# xl info
host                   : myhost.domain.com
release                : 2.6.32.43
version                : #6 SMP Tue Jul 26 13:43:40 BST 2011
machine                : x86_64
nr_cpus                : 4
nr_nodes               : 1
cores_per_socket       : 4
threads_per_core       : 1
cpu_mhz                : 2800
hw_caps                :
178bf3ff:efd3fbff:00000000:00001310:00802001:00000000:000037ff:00000000
virt_caps              : hvm
total_memory           : 7935
free_memory            : 1195
free_cpus              : 0
xen_major              : 4
xen_minor              : 1
xen_extra              : .1
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32
hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : unavailable
xen_commandline        : placeholder dom0_mem=512Mcc_compiler
: gcc version 4.3.2 (Debian 4.3.2-1.1)
cc_compile_by          : root
cc_compile_domain      : domain.com
cc_compile_date        : Tue Jul 26 10:42:19 BST 2011
xend_config_format     : 4
root@myhost:~#


root@myhost:~# xl list
Name                                        ID   Mem VCPUs      State
Time(s)
Domain-0                                    0   294     4     r-----
1287.3
Domu1                                       1  1019     2     -b----
89.4
Domu2                                       2   251     2     -b----
226.4
Domu3                                       3   763     4     -b----
266.0
Domu4                                       4   507     2     -b----
80.4
Domu5                                       5  1019     2     -b----
65.1
Domu6                                       6   113     1     -b----
4.3
Domu7                                       7   507     2     -b----
96.0
Domu8                                       8    49     1     -b----
4.0
Domu9                                       9  1019     4     -b----
190.0
Domu10                                    10  1019     2     -b----
28.1
root@myhost:~#


thanks

-----Original Message-----
From: Yi, Shunli [mailto:syi@xxxxxxxxxxxx]
Sent: 18 August 2011 07:08
To: Ian Tobin; Fajar A. Nugraha
Cc: Xen User-List
Subject: RE: [Xen-users] xen 4.1 missing memory

Try to paste the output of "xm info" and "xm list".

-Shunli

-----Original Message-----
From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Ian Tobin
Sent: Thursday, August 18, 2011 2:03 PM
To: Fajar A. Nugraha
Cc: Xen User-List
Subject: Re: [Xen-users] xen 4.1 missing memory

Hey,

I set the dom0 min men to 512m in xend-config.sxp and ballooning is
already enabled.  I rebooted and it initially shows 512m but one the vms
are booted it drops to 256 .

Any other thoughts?

Thanks

 




 


On 17 Aug 2011, at 10:44, "Fajar A. Nugraha" <list@xxxxxxxxx> wrote:

> On Wed, Aug 17, 2011 at 2:35 PM, Ian Tobin <itobin@xxxxxxxxxxxxx>
wrote:
>> Hi,
>> 
>> 
>> 
>> We have the dom0_mem=512M parameter set on boot which does show up 
>> after booting however ive noticed that it drops to roughly 256M on 
>> one of the boxes after the VMs are all started which is causing slow 
>> downs as it needs to swap.
> 
> IIRC that is expected behaviour, no matter what version the kernel is.
> 
>> The kernel is 2.6.32.43, has anyone else seen this?>
> dom0_mem only sets dom0's initial memory. If domU needs more memory,
> dom0 can still baloon down. See dom0-min-mem and 
> enable-dom0-ballooning on /etc/xen/xend-config.sxp to change this 
> behavior.
> 
> --
> Fajar
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
> 


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