The Aurora Project
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![[Disk QoS Project Logo]](diskqos.gif) |
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"Enforcing Quality of Service Guarantees in Storage Systems"
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Introduction
With system area networks (SANs) storage resources are being moved
from individual hosts to a shared pool, for both ease of
administration and economies of scale. This trend is causing many
applications to share each storage device. Such contention between
applications can cause poor performance, especially when some require
timely access to the devices, yet others are more relaxed. Enforcing
service level agreements (SLAs), or quality of service (QoS)
guarantees to partition resources between applications, and to ensure
those that need it have the timely access they require, can ease this
tension. The aim of this project is to develop mechanisms for
enforcing such guarantees in the disk drives or disk arrays, and a
suitable language for expressing application's requirements to the
system. The project may be conducted with the funding of Hewlett-Packard's Storage Systems
Program, and will be building upon past work conducted at the
University's computer laboratory, in particular the Desk Area Network (DAN), Pegasus and Measure
projects.
Timescale
The project will be conducted over three years, between
December 1998 and December 2001, at which point we hope to have
achieved:
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QoS specification suitable for enforcement in storage devices.
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Policing and enforcement mechanisms for the storage devices.
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Usage prediction mechanisms to provide statistical, or deterministic,
performance guarantees.
The key stages of the project are:
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July 1999
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Demonstration of a simple network-attached storage device cable of
enforcing simple Quality of Service policing between simultaneous
transaction streams.
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December 1999
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Evaluation of a QoS-enforcing scheduler when dealing with a range of
workloads. Clear identification of the scheduling parameters need to
enforce isolation between clients in the storage device.
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December 2000
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Show how service level agreements required by applications can be
translated into the scheduling parameters that the device operates
with.
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December 2001
Exhibit a scalable shared storage system with a basic admission
control scheme that can guarantee clients with predictable, yet
efficient service.
People
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Ian Pratt
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John Wilkes
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Dave Stewart
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Jean Bacon
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Principal Investigator
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Sponsor
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Research Student
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Supervisor
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| Lecturer and research fellow of King's
College, Cambridge UK. |
Of the Storage Systems Program of
Hewlett Packard's Computer Systems Laboratory, Palo Alto,
California. |
Of Churchill College, Cambridge UK. |
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Publications
Some of the related work conducted at the Computer Laboratory:
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The User-Safe Device I/O Architecture (Gzipped Postscript)
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Ian Pratt, dissertation submitted for the degree of Doctor of
Philosophy.
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User-Safe Devices for True End-to-End Qos (Gzipped Postscript)
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Ian Pratt, published in NOSSDAV '97.
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A Fresh Approach to File System Quality of Service (Text, Gzipped
Postscript)
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Paul Barham, published in NOSSDAV '97.
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The Desk Area Network (Compressed
Postscript)
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Mark Hayter, Derek McAuley, Cambridge University Computer Laboratory
Technical Report 228.
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Devices on The DAN (Postscript)
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Ian Pratt, slides for a talk given to the NISC NASD Working Group.
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Devices in a Multi-Service Operating System (Text, Gzipped
Postscript)
Paul Barham, Cambridge University Computer Laboratory Technical
Report 403.
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