[Pvfs2-users] PVFS2 directory attributes

[Tony Kew]

Dear Xuechen,

Just to add to Phil's info, there is (at least one) patch that you will 
have to
apply to pvfs 7.2.1 that fixes xattrs for the varstrip_dist distribution.
It is attached to the following message thread:
    http://osdir.com/ml/file-systems.pvfs2.users/2007-01/msg00050.html

You may find a page I wrote for internal testers at CCR helpful:

    
http://www.ccr.buffalo.edu/display/WEB/PVFS+version+2+scratch+filesystem+on+U2

There are examples there for varstrip_dist  there for a 16 node PVFS 
filesystem.




Tony

Tony Kew
SAN Administrator
The Center for Computational Research
New York State Center of Excellence
 in Bioinformatics & Life Sciences
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Phil Carns wrote:
> Hi Xuechen,
>
> I believe that this is possible with the varstrip distribution in 
> PVFS.  Here is some further information:
>
> http://www.pvfs.org/fisheye/browse/PVFS/doc/pvfs2-tuning.tex?r=1.1.22.1#l328 
>
>
> For example, I think on directory A you would set something like:
>
>   setfattr -n user.pvfs2.dist_name -v varstrip_dist A
>   setfattr -n user.pvfs2.dist_params -v "strips:0:64K;1:64K" A
>
> And this for B:
>
>   setfattr -n user.pvfs2.dist_name -v varstrip_dist B
>   setfattr -n user.pvfs2.dist_params -v "strips:2:64K;3:64K" B
>
> That should automatically set the number of datafiles to 2 based on 
> the distribution parameters, but it is possible that some previous 
> releases didn't do that.  If you have trouble use these commands to 
> make it explicit:
>
>   setfattr -n user.pvfs2.num_dfiles -v "2" A
>   setfattr -n user.pvfs2.num_dfiles -v "2" B
>
> A few other misc. pointers:
>
> - this only affects new files in any given directory and does not 
> change existing files
>
> - make sure to test the results by using "pvfs2-viewdist -f 
> <filename>" to see how new files are distributed
>
> -Phil
>
> Xuechen Zhang wrote:
>> There is a question about setting PVFS2 directory attributes. I have 
>> four I/O servers (0-3). I want to locate file A in directory A on 
>> server 0&1 and file B in directory B on server 2&3 by settting stripe 
>> distribution for the two directory. Can I implement this kind of 
>> distribution in PVFS2? If not, any suggestion for that? Thanks.
>>
>> Xuechen
>>
>>
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>>
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