Grid Storage API

The behavior of a storage system as seen by a data grid user is de ned by the
data grid storage API, which defi nes a variety of operations on storage systems
and le instances. Our understanding of the functionality required in this API is
still evolving, but it certainly should include support for remote requests to read
and/or write named fi le instances and to determine fi le instance attributes such as
size. In addition, to support optimized implementation of replica management
services (discussed below) we require a third party transfer operation used to
transfer the entire contents of a fi le instance from one storage system to another.

While the basic storage system functions just listed are relatively simple, various
data grid considerations can increase the complexity of an implementation. For
example, storage system access functions must be integrated with the security
environment of each site to which remote access is required. Robust performance
within higher-level functions requires reservation capabilities within storage
systems and network interfaces. Applications should be able to provide storage
systems with hints concerning access patterns, network performance, and so forth
that the storage system can use to optimize its behavior. Similarly, storage systems
should be capable of characterizing and monitoring their own performance; this
information, when made available to storage system clients, allows them to
optimize their behavior. Finally, data movement functions must be able to detect and
report errors. While it may be possible to recover from some errors within the
storage system, other errors may need to reported back to the remote application
that initiated the movement.