Re: [Xen-users] Maximum number of VMs per xen server

[Florian Heigl <florian.heigl@xxxxxxxxx>]

Can you try adding the xen command line options for increasing the xen
heap space?

http://support.citrix.com/article/CTX124259

There's a formula in that article that explains how much would be the
right amount.

florian

2012/3/8 moftah moftah <mofta7y@xxxxxxxxx>:
> Hi,
>
> It looks like I am having problems when I create more than 100 VM in
> one xen node.
>
> up to 60 VMs there is zero problems and between 60 and 100 problems start
>
> more than 100 the node becomes unstable.
>
> The node has tons of memory (more than 30 GB free)
> also the node has 16 cores so the processor isnt the issue here.
> is there any limitation in xen that prevent the system from serving
> more than 100 VMs ?
>
> the symptoms are that
> 1- xm command become ultra slow and we are forced to restart the xend
> demon regularly (xm create could take 5-20 min).
> 2- if we restart the node for any reason booting up all the VMs in
> /etc/xen/auto will take 4 hours or more if we didnt restart the xend
> demon in the middle.
> 3- the xend demon restart takes between 30 min up to 120 min.
> 4- after xend restart xm command bocomes fast for a while and start
> slowing again as we issue more m commands
>
> Dom-0 memory is 2 GB (i tried with 3 GB with no improvement at all)
>
> xm info result
> xm info
> host                   : localhost.localdomain
> release                : 2.6.32.18
> version                : #1 SMP Wed Aug 25 11:17:42 EDT 2010
> machine                : x86_64
> nr_cpus                : 24
> nr_nodes               : 4
> cores_per_socket       : 12
> threads_per_core       : 1
> cpu_mhz                : 2100
> hw_caps                :
> 178bf3ff:efd3fbff:00000000:00001310:00802001:00000000:000837ff:00000000
> virt_caps              : hvm
> total_memory           : 131070
> free_memory            : 112496
> node_to_cpu            : node0:0-5
>                         node1:6-11
>                         node2:18-23
>                         node3:12-17
> node_to_memory         : node0:20114
>                         node1:32671
>                         node2:29599
>                         node3:30110
> node_to_dma32_mem      : node0:3514
>                         node1:0
>                         node2:0
>                         node3:0
> max_node_id            : 3
> xen_major              : 4
> xen_minor              : 0
> xen_extra              : .1-rc5
> 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          : Mon Aug 02 11:18:11 2010 +0100 21294:f200573325ba
> xen_commandline        : dom0_mem=12048M loglvl=all guest_loglvl=all
> console=tty0 console=com2 com2=57600,8n1
> cc_compiler            : gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)
> cc_compile_by          : root
> cc_compile_domain      : localdomain
> cc_compile_date        : Sat Aug 21 23:10:21 EDT 2010
> xend_config_format     : 4
>
>
> any help will be appreciated
>
> Thanks
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxx
> http://lists.xen.org/xen-users



-- 
the purpose of libvirt is to provide an abstraction layer hiding all
xen features added since 2006 until they were finally understood and
copied by the kvm devs.

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