Dear PVFS2 users, After performing some experiments on OrangeFS 2.8.8, I am a little confused about the default distribution layout. Systems manual, change log, and some published papers claim that it should be ROUND_ROBIN. By that, I understand that a server is randomly chosen to store the first 64 KB of the file, and the second 64 KB block would be stored in the next server according to the order in the configuration file, and so on.
In my experiments, what I am observing is more close to the behavior I would expect with a RANDOM layout. For instance, when two out of four servers are chosen to store objects from a file, independently if the "user.pvfs2.num_dfiles" is set to 2 or if the file size is just 2x the stripe size, it seems like the two servers are being chosen randomly. It is worth noting that no change was performed in the generated config file; the number of data files is changed through setfattr commands before experiments. POSIX requests are being generated using the IOR benchmark v3.0.1 with MPICH 3.2, which, I am assuming, is not changing the layout of the file system. Attached, you will find some output that illustrate the aforementioned behavior. Any insight on this subject would be helpful. Best, -- Eduardo Camilo Inacio
manual_test_2stripes.out
Description: Binary data
manual_test_4stripes.out
Description: Binary data
_______________________________________________ Pvfs2-users mailing list [email protected] http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
