Hi Wantao, In the situation you describe a single request will be sent to each server for your application's I/O request. When accessing a file the client needs to know what datafile handles are associated with the file, done via a getattr request, after that the client can perform I/O without contacting the metadata server. However, if the client updates attributes (atime, mtime, etc) as typically happens when using the kernel client interface, there will be a setattr request to the metadata server.
Hope that helps, Michael On Wed, Jun 29, 2011 at 3:20 AM, Wantao <[email protected]> wrote: > Hi, all > > I have a PVFS2 installation with three IO servers and 64KB strip size. my > application requests 256KB in one IO operation(read or write). So, it needs > two continuous strips from server1 and one strip from server 2 and 3. In > this case, how many data transfer messages are needed for server1? Can it > send or receive two strips in one message? Another question is that when > accessing a big file, does PVFS2 need to interact with meta server for each > IO operation? > > Thanks for all advice. > > Wantao > > > > _______________________________________________ > Pvfs2-users mailing list > [email protected] > http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users > >
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