Livermore Computing Center 61
largest problem, and the network probably constrains only the top speed
(which no applications achieve in practice). For the case where an application
is running on a partition smaller than the entire system, and the applicaiton
will not be able to saturate bandwidth capability (as is possible with tens of
client nodes on a TLCC2 system), there will be file system bandwidth left for
each partition in the system.
Present application designers are adopting an N − M strategy where files
are shared over a subset of the N compute processes, resulting in a set of M
files smaller than the number of compute processes. This gives some latitude
to adapt to metadata performance constraints. Future applications will have
to move away from ...