[Pvfs2-users] Problems with basic distribution (with xattrs)

[Phil Carns]

Hi Tony,

Thanks for the bug report.  I have not looked at the varstrip issue yet, 
but the attached patch (also available in cvs head) should at least fix 
the basic_dist problem.

The problem was that basic_dist only works for files with 1 datafile, 
but the logic that lets it override the number of datafiles was 
happening before the directory hints were processed.

Someone correct me if I'm wrong, but I reorganized the code a little 
chose the number of datafiles in this priority (after making sure the 
final distribution for the file is set first, via hints or otherwise):

1) count specified in attr's passed into sys_create
    - example: -n option to pvfs2-cp
2) directory hints
    - example: "user.pvfs2.num_dfiles" extended attribute
3) mount options
    - example: num_dfiles option in /etc/pvfs2tab
4) system default
    - example: DefaultNumDfiles in server conf, or number of servers

The distribution itself gets a chance to override the value at the end 
if (as in the case of basic_dist) it doesn't support an arbitrary number 
of datafiles.

I'll look into the varstrip issue soon.

-Phil

Tony Kew wrote:
> Dear PVFS users list,
> 
> Mounting a pvfs 7.2.1, creating directories and setting the distribution
> type with setfattr for each directory, only simple_stipe and twod_stripe
> would allow me to write a file in the given directory.
> 
> Adding the varstrip_dist xattrs patch from Murali Vilayannur attached to
> this message thread:
> 
>    http://osdir.com/ml/file-systems.pvfs2.users/2007-01/msg00050.html
> 
> fixes the variable strip distibution, but the basic distribution still
> doesn't work for me.
> 
> The patch adds
> 
>    #include "pvfs2-dist-basic.h
> 
> to src/client/sysint/sys-create.sm so I wonder if no one has tried 
> this...???
> Perhaps there is a little more code needed to make basic_dist work with
> xargs?
> 
> The patch above is against 2.6, but works (and is needed for varstrip_dist
> with xargs) with 7.2.1  & the latest cvs (best I can tell) - perhaps 
> this patch
> could be added to both?
> 
> Let me know if there is useful debug info I can provide...
> 
> 
> Thanks Much
> Tony
> 
> Tony Kew
> SAN Administrator
> The Center for Computational Research
> New York State Center of Excellence
> in Bioinformatics & Life Sciences
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