Abstract
This thesis is about interaction between different architectures in
high performance computing for file system I/O. This is evaluated by
performance, scalability and fault handling. What excel in a loosely
coupled system fail in a tightly connected system and vice versa.
The I/O-path from disk to application have been examined both
theoretically and with tests for local and distributed file systems.
The impact of different levels of cache is shown using various tests.
This test results has been used to design and implement a protocol
giving SCI the semantics of TCP/IP, thereby replacing TCP/IP in
PVFS. SCI is a low latency, high throughput interconnect with
decentralized routing. In PVFS interconnect latency have only proven
important for meta data operations. For I/O operations the pipelining
hides the latency with the protocol window. PVFS have as expected
shown increased read and write performance with increased interconnect
throughput. Throughput have been increased by a factor of 5 by
introducing SCI from 100Mb/s Ethernet. To limit overloading in the
interconnect, two different techniques have been evaluated. Exponential backoff as in TCP/IP and a token based scheme.