[Pvfs2-developers] [PATCH] modify twod-stripe's default params and add some documentation

[Sam Lang]

Kyle,

How is this patch useful for you guys?  With a single server (and only  
one stripe), it doesn't matter what the factor and num_groups are,  
does it?  It still behaves the same as simple-stripe in that case.   
With multiple servers setting the factor and num_groups to 1 does make  
the 2d distribution act like simple-stripe, but why not just use  
simple stripe in that case?

-sam


On Jul 1, 2008, at 3:19 PM, Kyle Schochenmaier wrote:

> Patch is against cvs head, and modifies the default num_groups to be 1
> and the group_strip_factor = 1  so twod-stripe's defaults still work
> when you use it on a single-server, it will now by default behave the
> same as simple-stripe until the user modifies the num_groups and
> strip_factor xattrs.
>
> Also added a brief description of the definitions for the dist_params
> in twod-stripe.
>
> Tested fully functional on my servers.
>
> Kyle
>
>
> Index: src/io/description/dist-twod-stripe.c
> ===================================================================
> RCS file: /anoncvs/pvfs2/src/io/description/dist-twod-stripe.c,v
> retrieving revision 1.5
> diff -r1.5 dist-twod-stripe.c
> 6a7,15
>> /* twod-stripe will take all of the servers in the filesystem and
>> * partition them into num_groups groups.  Data will then be striped  
>> to
>> * each group before we move onto the next group.  The strip_factor  
>> will
>> * determine how many chunks of strip_size are written to each server
>> * in each group before we transition to the next group.
>> * The striping on the group level is done round-robin in the same
>> * fashion as simple-stripe
>> */
>>
>
>
> Index: include/pvfs2-dist-twod-stripe.h
> ===================================================================
> RCS file: /anoncvs/pvfs2/include/pvfs2-dist-twod-stripe.h,v
> retrieving revision 1.4
> diff -r1.4 pvfs2-dist-twod-stripe.h
> 17c17
> < #define PVFS_DIST_TWOD_STRIPE_DEFAULT_GROUPS 2
> ---
>> #define PVFS_DIST_TWOD_STRIPE_DEFAULT_GROUPS 1
> 19c19
> < #define PVFS_DIST_TWOD_STRIPE_DEFAULT_FACTOR 256
> ---
>> #define PVFS_DIST_TWOD_STRIPE_DEFAULT_FACTOR 1
>
>
> -
> Kyle Schochenmaier
> <twod-dist.patch>_______________________________________________
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