[Pvfs2-developers] Sys create setting the datafile nodes depending on interface call.

[Murali Vilayannur]

Hi Julian,

> Yes they are, but if we extend the system interface then we could easily add
> another parameter if necessary and pending changes to the system interfaces
> can be done in one modification. Thats why I was asking.

Ok, if you say so :).
I suppose if everybody agrees to this interface change do
send a patch ;)!

> > Can you tell us what exactly was the problem with the new distribution?
> I was thinking that all distributions could benefit from such a mechanism.
> Maybe the metatdata server for that file could be selected on the same way,
> too ?
> Within the distribution itself the server names are not available I guess, so
> there has to be some hack code outside. Also, I think due to dynamic
> migration etc. it is no good idea to write a distribution which fixated the
> datafiles.

> This might be possible and is a another cool way, however we want the user to
> set it for example with MPI_hints before the file is opened and only to set
> it for a single file. For example somehow to use dedicated servers for this
> file of a single file system, this might be used to place the datafiles on
> the same nodes if the client also acts as a server or to place the
> datafiles "close" to the client on a dataserver. It seems to be rather
> inefficent to change the extended attributes of a directory then create the
> file and change it back.

I am not sure how many people are going to use or require this
feature. I really wish we could come up with something cleaner though.

Perhaps, we can create a new structure like PVFS_hints (that groups all
these extra parameters as they come by) and pass an optional
pointer to that at the time of sys_create, sys_mkdir and sys_symlink()?
thanks,
Murali