Hi Julian, Okay. I think I understood. Thanks for the clarification! Can you send the migration tool as well or check that in to your branch? Or did I miss that? Thanks, Murali
On Mon, 28 Aug 2006, Julian Martin Kunkel wrote: > Hi, > > Could you rephrase the above? I dont think I understand what it means.. > Sorry for the weird phrases. I give it a new shot from the clients point of > view. > At the beginning of an I/O request the client already requests the files array > of datafiles from the metadata server. > Now the I/O starts in parallel to all participating dataservers. If one > dataserver returns the error ENOENT during the first acknowlege or during the > flow this could be marked in the context struct of this I/O operation. Also > the client could starts from init again, now it knows that either the I/O has > to be retried or that at least one dataserver reports ENOENT. > If one reported ENOENT then the client invalidates the acache entry. > In addition the server could copy the old dfile array into a new one or just > create a new one for the next steps. > Now the client getattr sm fetches the datafile array again from the > metaserver. For each I/O operation which reports ENOENT the client compares > old datafile with the new datafile, if they match we know ENOENT is not > caused by a migration, because in this case they have to be different. > > (I know it is not completely guaranteed that the metadata server has rewritten > the datafile location in the current implementation (it is very unlikely that > it happen), but I will do so in the final implementation by adding another > message exchange between metadata server and old dataserver) > > Enjoy the day, > Julian > _______________________________________________ > Pvfs2-developers mailing list > [email protected] > http://www.beowulf-underground.org/mailman/listinfo/pvfs2-developers > > _______________________________________________ Pvfs2-developers mailing list [email protected] http://www.beowulf-underground.org/mailman/listinfo/pvfs2-developers
