[one-users] Xen problem - Dom0 using up all memory on Scientific Linux

makhanmail makhanmail at gmail.com
Thu Jan 21 13:00:27 PST 2010


Hi Tres,

Of course you're right.
You've been most helpful, thanks.

Best regards,
Maciej




Dnia 21-01-2010 o 21:37:50 Tres Wong-Godfrey <tres at blas.phemo.us>  
napisał(a):

>
> Hi Maciej,
>
> I believe the issue is Xen's default configuration. By default it will  
> reserve all memory to dom0 & dynamically allocate it to domU as they get  
> created. To fix, you just need to statically define the maximum memory  
> available to dom0.
>
> To fix this, just pass a kernel parameter on boot. Edit the Xen kernel  
> definition in /boot/grub/grub.conf and add dom0_mem=XXXMB. So for  
> example on my CentOS hardware nodes I have:
>
>        kernel /xen.gz-2.6.18-128.4.1.el5 dom0_mem=256MB
>
> Regards,
> Tres
>
> Tres Wong-Godfrey
>
> On Jan 21, 2010, at 12:11 PM, makhanmail wrote:
>
>> Hi again,
>>
>> I got another problem with configuration of my new cloud. Although  
>> there is no big process running in the system, xentop states the  
>> Domain-0 is using up 95% of the RAM. The same thing is happening on two  
>> completely different servers, so I think it may have something to do  
>> with OS, which is Scientific Linux 5.4.
>>
>> Do you know what may be the cause and how to fix this?
>>
>> Regards,
>> Maciej
>>
>>
>>
>>
>> [root at phrixus ~]# xentop -bi1
>> xentop - 20:53:57   Xen 3.1.2-164.2.1.el5
>> 1 domains: 1 running, 0 blocked, 0 paused, 0 crashed, 0 dying, 0  
>> shutdown
>> Mem: 16776548k total, 16383780k used, 392768k free    CPUs: 8 @ 2666MHz
>>      NAME  STATE   CPU(sec) CPU(%)     MEM(k) MEM(%)  MAXMEM(k)  
>> MAXMEM(%) VCPUS NETS NETTX(k) NETRX(k) VBDS   VBD_OO   VBD_RD   VBD_WR  
>> SSID
>>  Domain-0 -----r        650    0.0   16038912   95.6   no limit        
>> n/a     8    5    16244    94733    0        0        0        0    0
>>
>> [root at phrixus ~]# free
>>             total       used       free     shared    buffers     cached
>> Mem:      16038912    1451612   14587300          0     196588      
>> 669004
>> -/+ buffers/cache:     586020   15452892
>> Swap:     18481144          0   18481144
>>
>> [root at phrixus ~]# xm info
>> host                   : phrixus
>> release                : 2.6.18-164.2.1.el5xen
>> version                : #1 SMP Tue Sep 29 19:06:31 EDT 2009
>> machine                : x86_64
>> nr_cpus                : 8
>> nr_nodes               : 1
>> sockets_per_node       : 2
>> cores_per_socket       : 4
>> threads_per_core       : 1
>> cpu_mhz                : 2666
>> hw_caps                :  
>> bfebfbff:20000800:00000000:00000140:000ce3bd:00000000:00000001
>> total_memory           : 16383
>> free_memory            : 383
>> node_to_cpu            : node0:0-7
>> xen_major              : 3
>> xen_minor              : 1
>> xen_extra              : .2-164.2.1.el5
>> 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_pagesize           : 4096
>> platform_params        : virt_start=0xffff800000000000
>> xen_changeset          : unavailable
>> cc_compiler            : gcc version 4.1.2 20080704 (Red Hat 4.1.2-46)
>> cc_compile_by          : brewbuilder
>> cc_compile_domain      : fnal.gov
>> cc_compile_date        : Tue Sep 29 18:42:12 EDT 2009
>> xend_config_format     : 2
>>
>>
>> [root at phrixus ~]# lsb_release -a
>> LSB Version:     
>> :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
>> Distributor ID: ScientificSL
>> Description:    Scientific Linux SL release 5.4 (Boron)
>> Release:        5.4
>> Codename:       Boron
>>
>> [root at phrixus ~]# uname -a
>> Linux phrixus 2.6.18-164.2.1.el5xen #1 SMP Tue Sep 29 19:06:31 EDT 2009  
>> x86_64 x86_64 x86_64 GNU/Linux
>>
>>
>> [root at nephele ~]# xentop -bi1
>> xentop - 21:01:49   Xen 3.1.2-164.2.1.el5
>> 1 domains: 1 running, 0 blocked, 0 paused, 0 crashed, 0 dying, 0  
>> shutdown
>> Mem: 4192600k total, 3799740k used, 392860k free    CPUs: 4 @ 2394MHz
>>      NAME  STATE   CPU(sec) CPU(%)     MEM(k) MEM(%)  MAXMEM(k)  
>> MAXMEM(%) VCPUS NETS NETTX(k) NETRX(k) VBDS   VBD_OO   VBD_RD   VBD_WR  
>> SSID
>>  Domain-0 -----r       2297    0.0    3665920   87.4   no limit        
>> n/a     4    6     8843   434339    0        0        0        0    0
>>
>> [root at nephele ~]# free
>>             total       used       free     shared    buffers     cached
>> Mem:       3665920    1336244    2329676          0     243360      
>> 706732
>> -/+ buffers/cache:     386152    3279768
>> Swap:      6062072          0    6062072
>>
>> [root at nephele ~]# xm info
>> host                   : nephele.ifj.edu.pl
>> release                : 2.6.18-164.2.1.el5xen
>> version                : #1 SMP Tue Sep 29 19:06:31 EDT 2009
>> machine                : x86_64
>> nr_cpus                : 4
>> nr_nodes               : 1
>> sockets_per_node       : 1
>> cores_per_socket       : 4
>> threads_per_core       : 1
>> cpu_mhz                : 2394
>> hw_caps                :  
>> bfebfbff:20100800:00000000:00000140:0000e3bd:00000000:00000001
>> total_memory           : 4094
>> free_memory            : 383
>> node_to_cpu            : node0:0-3
>> xen_major              : 3
>> xen_minor              : 1
>> xen_extra              : .2-164.2.1.el5
>> 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_pagesize           : 4096
>> platform_params        : virt_start=0xffff800000000000
>> xen_changeset          : unavailable
>> cc_compiler            : gcc version 4.1.2 20080704 (Red Hat 4.1.2-46)
>> cc_compile_by          : brewbuilder
>> cc_compile_domain      : fnal.gov
>> cc_compile_date        : Tue Sep 29 18:42:12 EDT 2009
>> xend_config_format     : 2
>>
>>
>>
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