[PVFS2-developers] possible new config file options?

[dhildebz at eecs.umich.edu]

Hello,
If you guys are going to have a distribution section, why not provide support
for each distribution to specify a list of variables that are specific to each
distribution.   Maybe the PVFS2 code that reads in the name/value pairs can
pass them (in a hashtable or something) to the distribution code.  I can
imagine distributions that would like to be able to customize more parameters
than just stripe size and # iods per file.

Dean
Quoting Brad Settlemyer <bradles at parl.clemson.edu>:

> Hello
>
>   RobR and I were speaking about this yesterday.  I have no complaints
> about what you're choices, though I would like to point out that the
> number of dfiles selected is semi-dependent on the distribution -- that
> is the distribution gets a shot to verload the value if it so chooses.
> For that reason, we had kind of discussed making the default number of
> dfiles a distribution setting:  (I don't know the config-file format, so
> excuse any mistakes)
> <distribution>
>   <simple_stripe>
> 	strip_size xxx
> 	num_dfiles xxx
>
> You actually make a very good point that the number of dfiles is not an
> explicit parameter to the distribution, but it is in fact set (even in
> the simple_stripe case) by distribution code.
>
> Your way is probably still better tho, as simple stripe simply uses the
> default dfile selecter, which chooses all I/O servers, custom
> distributions would then still override that setting, and could provide
> it as their own param as well if neccesary.
>
> So basically, I like how you've proposed it!
>
> (I'm also going to attempt to make the default number of dfiles client
> configurable in the pvfs2tab -- with dists and hints still able to
> overload the value, tho I haven't worked out how exactly quite yet)
>
> Cheers,
> Brad
>
> On Thu, 2005-06-16 at 19:57 +0200, Phil Carns wrote:
> > It seems like the server configuration files need a few more tunable
> > options at this point.  David Metheny and I spent some time
> > brainstorming and came up with the list below for high level parameters.
> >   We didn't worry about flow/bmi/trove options.
> >
> > Any comments?
> >
>
> > 2) default distribution type and parameters: On a per file system level,
> > it would be nice to be able to chose the default distribution as well as
> > arbitrary parameters to go with it.  There could be multiple "Param"
> > keywords, and the strings following them will be given to distribution
> > specific code to handle so that the conf parser doesn't have to be
> > updated each time a distribution is added.
> >
> > <FileSystem>
> > ...
> > <DefaultDistribution>
> > Name simple_stripe
> > Param strip_size 65536
> > </DefaultDistribution>
> > </FileSystem>
> >
>
> > 4) default number of datafiles: On a per file system basis, how many
> > datafiles should be chosen per file.  The system interface would still
> > be able to override this option:
> >
> > <FileSystem>
> > ...
> > DefaultNumDataFiles 4
> > </FileSystem>
> >
>
>
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