Cuneyt Akinlar

A scalable distributed multimedia file system using network attached autonomous disks

Repositories for multimedia data differ from those for traditional text-based data both in terms of storage space and streaming bandwidth requirements. The file systems used in the multimedia environment need to support large volumes and high bandwidth. In this paper, we propose a novel scalable distributed file system built using autonomous disks. Autonomous disks are attached directly to the network and are able to perform lightweight processing. We discuss different ways to realize an autonomous disk, and describe a prototype implementation on a Linux platform using PC-based hardware. We present the design methodology and a prototype Linux-based implementation of the distributed file system that supports such disks. We detail experimental results on the performance of the proposed file system prototyped using autonomous disks. We show that the performance of the file system scales linearly with the number of disks and the number of clients. The file systems performance is much superior to NFS running on the same hardware platform, and it can deliver higher raw disk bandwidth to the applications. We also show that the file system can provide strict bandwidth guarantees for multimedia streams.

Benchmarking a network of PCs running parallel applications

Presents a benchmarking study that compares the performance of a network of four PCs connected by a 100 Mbit/s fast Ethernet running three different system software configurations: TCP/IP on Windows NT, TCP/IP on Linux and a lightweight message-passing protocol (U-Net active messages) on Linux. For each configuration, we report results for communication micro-benchmarks and the NAS (Numerical Aerodynamics Simulation) parallel benchmarks. For the NAS benchmarks, the overall running time using Linux TCP/IP was 12-500% less than the Windows NT TCP/IP configuration. Likewise, the Linux U-Net based message-passing protocol outperformed the Linux TCP/IP version by 5-200%+. We also show that, by using Linux U-Net, we are able to achieve 125 /spl mu/s latency between two processes using PVM. Finally, we report that the default mathematical libraries supplied with NT (for both gcc and Visual C++) are substantially slower than the one supplied with Linux.

A scalable bandwidth guaranteed distributed continuous media file system using network attached autonomous disks

Repository for continuous media data differs from that of the traditional text-based data both in storage space and streaming bandwidth requirements. The file systems used for continuous media streams need to support large volumes and high bandwidth. We propose a scalable distributed continuous media file system built using autonomous disks. Autonomous disks are attached directly to the network and are able to perform lightweight processing. We discuss different ways to realize the autonomous disk, and describe a prototype implementation on a Linux platform using PC-based hardware. We present the basic requirements of the continuous media file system and present the design methodology and a prototype Linux-based implementation of the distributed file system that supports the requirements. We present experimental results on the performance of the proposed file system prototyped using autonomous disks. We show that the performance of the file system scales linearly with the number of disks and the number of clients. The file system performs much superior to NFS running on the same hardware platform and can deliver higher raw disk bandwidth to the applications. We also present bandwidth and time sensitive read/write procedures for the file system and show that the file system can provide strict bandwidth guarantees for continuous media streams.

Bandwidth guarantee in a distributed multimedia file system using network attached autonomous disks

File systems for multimedia applications must support high bandwidth streaming with strict rate guarantees. Recently we proposed a distributed file system built using autonomous disks (S. Mukherjee et al., 1999). Autonomous disks are attached directly to the network and are able to perform lightweight processing. The paper describes the methodologies used to make the file system quality of service (QoS) aware and real-time sensitive. We propose efficient bandwidth allocation and enforcement policies that can keep the servers stateless. The policies are implemented in Linux kernel along with the file system. Using experimental results we show the effectiveness of the policies, and the enforcement of bandwidth allocation and usage in a fair manner. We also show that the overhead of the proposed mechanism on the overall system performance is very minimal.

IP address configuration algorithms for routerless and single-router zeroconf networks

IP hosts and network infrastructure have historically been difficult to configure, requiring network services such as DHCP and DNS servers, and relying on highly trained network administrators. This need for administration has prevented IP networks from being used in many environments such as in homes, in small businesses, in impromptu networks established at conferences, construction sites, emergency relief stations, etc. With the proliferation of IP-enabled network-attached appliances and inexpensive computing devices, the demand to enable plug-and-play, easy-to-use IP networking has increased. This demand has initiated a new paradigm of IP networking called zero configuration, or zeroconf, networking. The goal is to develop a set of zeroconf configuration protocols to enable IP networking without manual configuration or administration. Such IP networks are called zeroconf networks. We examine IP address configuration in zeroconf networks involving two network topologies: (1) A routerless network, which consists of several hosts attached to a segment having no router, (2) A single-router network, which consists of a router joining several segments together into a star-shaped topology. We suggest the requirements for IP address configuration, review the existing solutions, and propose new algorithms to address their deficiencies. Finally, we present a comparison of our algorithms to existing solutions and describe when a particular configuration method should be used.

An IP address configuration algorithm for multi-router zeroconf networks

Zero-configuration (zeroconf) networks are a particular class of IP networks that do not require any user administration for correct operation. IP address configuration in zeroconf networks is an important problem. While there are a few proposals for IP host configuration, a general solution for IP router configuration, an important problem in multi-router zeroconf networks, does not yet exist. In a single-router zeroconf network, the router can easily configure by creating unique IP subnets over each of its directly attached segments. But when several such self-configuring routers are interconnected together to form a multi-router network, there is a need for (1) dynamic exchange of routing information among the routers and (2) consistent assignment of IP subnets in the network, i.e., an IP subnet can not be assigned to different segments. As new routers are added to the zeroconf network, any IP subnet conflicts must be detected and resolved. No solutions for IP address auto-configuration of multi-router networks exist. This paper suggests the requirements for IP address configuration of multi-router zeroconf networks, and proposes IP host and router configuration algorithms to satisfy these requirements. Among the proposed algorithms is a novel routing algorithm designed by augmenting the basic distance vector routing algorithm that can solve both the problem of dynamic routing and consistent IP subnet assignment in multi-router zeroconf networks. We also show how the popular routing information protocol (RIP) can be augmented to implement the proposed routing algorithm, called the zeroconf routing information protocol (ZRIP).