Re: [Xen-users] limit of domUs ?

[Yura Pismerov <y.pismerov@xxxxxxxxxxxxx>]

Petersson, Mats wrote:
> What amount of memory have you given to Dom0? If Dom0 starts out with a
> lot of memory, it's quite likely that it's not going to shrink to
> "nothing" when more memory is needed by DomU's. 
>   

I tried 256 and 512 - it does not make any difference.
Besides, there is a few gigs of RAM available (according to xentop) by
the time I get the error.

> As far as I'm aware, the number of domains should be limited only by the
> available memory. 
>
> However, there's also the Xen internal heap. It's default size is 12MB,
> and it's not adjustable at run-time or by boot parameter[1]. I guess you
> could change the source [.../xen/include/asm-x86/config.h:
> XENHEAP_DEFAULT_MB - which is defined as DIRECTMAP_MBYTES, which is 12
> in my version of the source code (fairly recent). 
>
> [1] If you're running x86_64 or IA64 it IS adjustable, but not in 32-bit
> kernel version. Don't ask me why that is... But Keir stated more than
> once that they are not going to change the size of the heap, so I guess
> it's that size for a good reason... If you're running x86_64/IA64, the
> parameter to the kernel is xenheap_megabytes, and it takes an integer
> number. 
>   

I run x86_64, so I will try to adjust that parameter.
Thanks.


> --
> Mats
>
>   
>> -----Original Message-----
>> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
>> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
>> Yura Pismerov
>> Sent: 05 June 2006 15:29
>> To: 'xen-users@xxxxxxxxxxxxxxxxxxx'
>> Subject: [Xen-users] limit of domUs ?
>>
>>
>> What is the max number of domains one can create in Xen 3.0.2 ?
>> For some reason, no matter what amount of RAM I allocate for 
>> the domU's I can only create about 100 of them.
>> After that I receive  "Error: (12, 'Cannot allocate 
>> memory')", even though there is still plenty of free RAM available.
>> Where should I look ?
>>
>>
>>
>> _______________________________________________
>> Xen-users mailing list
>> Xen-users@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-users
>>
>>
>>     
>
>   


-- 
Yuri Pismerov, System Administrator
Armor Technologies (Canada) Inc.

P: 905 305 1946 (x.3519)
http://www.armorware.net

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