[Pvfs2-developers] TroveMethod configuration parameter

[Phil Carns]

I have some questions about the TroveMethod parameter.

It looks like it can be specified either in the <Defaults> section or 
the <StorageHints> section.  I added some gossip prints to Trove's 
initialize() and collection_lookup() functions to see what these 
correspond to:

- TroveMethod in <Defaults> toggles the value passed to initialize()
- TroveMethod in <StorageHints> toggles the value passed to 
collection_lookup()

Both of these default to "dbpf" if not specified in the configuration file.

Is the collection_lookup() value (and therefore the <StorageHints> 
section of the config file) the one that actually impacts I/O in the 
server?  I am assuming so, because you may have multiple collections and 
it makes sense to be able to specify a different method for each one.

The pvfs2-genconfig utility places TroveMethod option in the <Defaults> 
section.  Is this intentional?  For example, if someone edited a 
configuration file created by genconfig, they might try to change the 
value of TroveMethod from "dbpf" to "alt-aio".  However, it doesn't look 
like this would have any real impact.  It would change the parameter to 
trove's initialize() function, but the collection_lookup() would still 
default to the dbpf method.

-Phil