Non-Contiguous I/O Support for Object-Based Storage

The access patterns performed by disk-intensive applications vary widely, from simple contiguous reads or writes through an entire file to completely unpredictable random access. Often, applications will be able to access multiple disconnected sections of a file in a single operation. Application programming interfaces such as POSIX and MPI encourage the use of non-contiguous access with calls that process I/O vectors. Under the level of the programming interface, most storage protocols do not implement I/O vector operations (also known as scatter/gather). These protocols, including NFSv3 and block-based SCSI devices, must instead issue multiple independent operations to complete the single I/O vector operation specified by the application, at a cost of a much slower overall transfer time. Scatter/gather I/O is critical to the performance of many parallel applications, hence protocols designed for this area do tend to support I/O vectors. Parallel Virtual File System (PVFS) in part...

• Type: Conference
• Year: 2008
• Where: ICPPW
• Authors: Dennis Dalessandro, Ananth Devulapalli, Pete Wyckoff
• Keywords: Distributed And Parallel Computing, I/o Vector Operation, I/o Vectors, ICPPW 2008, Parallel Virtual File System