Matthieu:

If you are using OrangeFS 2.8.7, then you can use the pvfs usr library.
The library calls are the preferred way to directly call the filesystem.
Please take a look at
http://www.orangefs.org/trac/orangefs/wiki/Posix-like%20APIs.  This wiki
page will describe how to get started with the usr library.

If you have questions, feel free to write back.

Becky

On Thu, Feb 7, 2013 at 11:53 AM, Becky Ligon <[email protected]> wrote:

> Matthieu:
>
> Look at the Orangefs.org wiki page on distributions and layouts.  This
> page describes how you can specify the different options when creating a
> file using the API. (
> http://www.orangefs.org/trac/orangefs/wiki/Distributions)
>
>
> Becky
>
>
> On Thu, Feb 7, 2013 at 11:37 AM, Kyle Schochenmaier <[email protected]>wrote:
>
>> Hi Mattieu -
>>
>> I'm not sure if a 0 size will work, in fact, if it wasnt designed in it
>> may crash things (I havent looked at this distribution's code in years).
>>
>> Moreover, the server numbers you're seeing in the example are the servers
>> in the 'stripe' but may not correspond to the logical server numbers that
>> you're thinking of.
>> This is because the '0th' server in the stripe is determined
>> randomly among the set of servers in the filesystem and intentionally
>> changes so as to avoid hitting the same server repeatedly for every file
>> creation, or in the case of many small files that dont fill an entire
>> stripe this prevents uneven distribution of the file handles.
>>
>> Regards,
>> ~Kyle
>>
>>
>> Kyle Schochenmaier
>>
>>
>> On Thu, Feb 7, 2013 at 10:30 AM, Matthieu Dorier <
>> [email protected]> wrote:
>>
>>> Hi Kyle,
>>>
>>> Thank you for the advice, these codes should be indeed a good place to
>>> start.
>>>
>>> Regarding the distribution, I dug a bit and found here
>>> http://www.orangefs.org/doxygen/index.html some functions to set/get
>>> extended attributes (e.g. pvfs_fsetxattr). Then at
>>> http://www.pvfs.org/cvs/pvfs-2-8-branch-docs/doc/pvfs2-tuning/pvfs2-tuning.htmlin
>>>  section 7.4 I see a way to set the stripe size on a per-server basis so
>>> I guess I could put 0 for the servers I don't want to use and a positive
>>> value for the servers I want to use. Would that work?
>>>
>>> Thanks,
>>>
>>> Matthieu
>>>
>>> ------------------------------
>>>
>>> *De: *"Kyle Schochenmaier" <[email protected]>
>>> *À: *"Matthieu Dorier" <[email protected]>
>>> *Cc: *"pvfs2-users" <[email protected]>
>>> *Envoyé: *Jeudi 7 Février 2013 17:05:06
>>> *Objet: *Re: [Pvfs2-users] Using PVFS2's API directly
>>>
>>>
>>> Hi Matthieu -
>>>
>>> For API examples I would start with looking at the admin tools  like
>>> pvfs2-cp, etc as they utilize the libpvfs apis directly.
>>>
>>> I'm not sure if you're able to specify any of the information you want
>>> to on a per-file basis at creation time.
>>> This information is pulled in from the distribution params of the
>>> directory the file is created in.  There may be other methods I'm not
>>> immediately thinking of though... I'll let others comment.
>>>
>>> ~Kyle
>>>
>>> Kyle Schochenmaier
>>>
>>>
>>> On Thu, Feb 7, 2013 at 7:05 AM, Matthieu Dorier <
>>> [email protected]> wrote:
>>>
>>>> Hi,
>>>>
>>>> I would like to use the client API provided by PVFS2, without any
>>>> kernel support or MPI-I/O interface. Where can I find documentation and
>>>> code samples of this API?
>>>> Also I'd like to know if there is a way to specify, when creating a
>>>> file (so from within a client application), the list of storage servers to
>>>> which this file should go and the stripe size, in order to bypass the
>>>> configuration of the directory in which the file is created?
>>>>
>>>> Thanks!
>>>>
>>>> Matthieu Dorier
>>>> PhD student at ENS Cachan Brittany and IRISA
>>>> http://people.irisa.fr/Matthieu.Dorier
>>>>
>>>> _______________________________________________
>>>> Pvfs2-users mailing list
>>>> [email protected]
>>>> http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
>>>>
>>>>
>>>
>>>
>>
>> _______________________________________________
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>> [email protected]
>> http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
>>
>>
>
>
> --
> Becky Ligon
> OrangeFS Support and Development
> Omnibond Systems
> Anderson, South Carolina
>
>


-- 
Becky Ligon
OrangeFS Support and Development
Omnibond Systems
Anderson, South Carolina
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