Hi all, We are using MPI-IO on Lustre, so that we can achieve good performance when writing or reading the same file from multiple processes and clients. In the shared pointers read/write routines, MPI-IO makes an intensive use of file locks (for instance, see the file src/mpi/romio/adio/common/ad_get_sh_fp.c from mpich2-1.0.7). The problem is that file locking support in Lustre is very limited today: - there is the localflock option for the local mode. In this mode, locks are coherent on a node (a single-node flock), but not across all clients; - there is the flock option for the consistent mode. In this mode, locks are coherent across all clients. But the Lustre Operations Manual includes a big warning about this mode, saying that it can affect performance and stability.
That being said, does anybody in the Lustre community know about current alternatives to the MPI-IO shared pointers read/write routines, which do not use the file locking mechanism but provide the same functionality? By the way, do we have an idea of the Lustre version that will provide the reliable version of the flock consistent mode? Best regards, Sebastien. _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
