[one-users] SCP bottleneck

Ruben S. Montero rubensm at dacya.ucm.es
Tue Sep 21 13:15:29 PDT 2010


Hi,

I agree with Stefan, multiple scp's usually will require some tunning
at the TM level to speed up things. Unfortunately this strongly
depends on your setup.

A kind of work around (also suggested by Stefan) is to limit the
number of simultaneous deployments. This can be done with the new
scheduler with -d option (check [1]). Also take into account that you
should also adjust -t so the deployment of VM finishes before you
start the next one...

Cheers

Ruben

[1] http://www.opennebula.org/documentation:rel2.0:schg

On Tue, Sep 21, 2010 at 12:57 PM, Stefan Freitag <stefan.freitag at udo.edu> wrote:
> Hi Luis,
>
> in Dortmund we have ~250 physical nodes and transfer at the moment the VM
> (8 GByte per Image) images via SSH to the nodes. Due to the load caused by
> the SSH transfers we limit the number of VMs deployed in parallel to two.
> Three or four VMs in parallel should also be possible, but (hopefully) in
> very near future we will migrate to another setup:
> then scp-wave will be used in the background to transfer the images to the
> physical nodes and a "home-brewn" tm mechanism will put in place to start
> the VMs on the nodes.
>
> Cheers
> Stefan
>
>
> Luis M. Carril schrieb:
>>   Hello,
>>
>>      We've a OpenNebula 2.0 cluster  in SSH mode and when we deploy near
>> simultaneously 3 or 4 MVs of about 1GB, sometimes some of the
>> deployments fail because SSH/SCP connection timeouts.
>>      I've seen in diferent slides that is possible to make TM plugins
>> based on parallel-ssh or bittorrent.
>>
>>      Has anyone experimented similar problems, or developed some of
>> these plugins?
>>
>> Best regards
>>
>> --
>> Luis M. Carril
>> Técnico Superior
>> Centro de Supercomputacion de Galicia (CESGA)
>> Avda. de Vigo s/n
>> 15706 Santiago de Compostela
>> SPAIN
>>
>> Tel: 34-981569810
>> lmcarril at cesga.es
>> www.cesga.es
>>
>>
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>>
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>
>
> --
> Dipl.-Inform. Stefan Freitag
> Institut für Roboterforschung - Abteilung Informationstechnik
> Universitaet Dortmund         | phone:  +49 (0)231-755-7009
> Otto-Hahn-Str. 8              | mobile: +49 (0)176-23900074
> 44221 Dortmund, Germany       | fax:    +49 (0)231-755-3251
> www.irf.uni-dortmund.de       | email:  stefan.freitag at udo.edu
>
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-- 
Dr. Ruben Santiago Montero
Associate Professor (Profesor Titular), Complutense University of Madrid

URL: http://dsa-research.org/doku.php?id=people:ruben
Weblog: http://blog.dsa-research.org/?author=7



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