Directly-attached (local) storage generally performs 
better than remote storage because it is simpler to configure well and avoids 
communications overheads.

Some remote storage performs very poorly, especially 
under the kind of load that {es} imposes. However, with careful tuning, it is 
sometimes possible to achieve acceptable performance using remote storage too. 
Before committing to a particular storage architecture, benchmark your system 
with a realistic workload to determine the effects of any tuning parameters. If 
you cannot achieve the performance you expect, work with the vendor of your 
storage system to identify the problem.