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In Workshop on Software Engineering for Automotive Systems, International Conference on Sofware Engineering (May 2004)
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In Proceedings of the 3rd USENIX Workshop on Real Large Distributed Systems (December 2006)
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Abstract
The primary motivation for enterprises to adopt virtualization technologies is to create a more agile and dynamic IT infrastructure -- with server consolidation, high resource utilization, the ability to quickly add and adjust capacity on demand -- while lowering total cost of ownership and responding more effectively to changing business conditions. However, effective management of virtualized IT environments introduces new and unique requirements, such as dynamically resizing and migrating virtual machines (VMs) in response to changing application demands. Such capacity management ...
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Modeling, Analysis, and Simulation of Computer and Telecommunications Systems, 2004. (MASCOTS 2004). Proceedings. The IEEE Computer Society's 12th Annual International Symposium on In Proceedings of the 12th IEEE Annual International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunications Systems (2004), pp. 275-283, doi:10.1109/mascot.2004.1348282
Abstract
One of the primary challenges facing scalable network emulation and simulation is the overhead of storing network-wide routing tables or computing appropriate routes on a per-packet basis. We present an approach to routing table calculation and storage based on spanning tree construction that provides an order of magnitude reduction in routing table size for Internet-like topologies. In our approach, we maintain a variable number of spanning trees for a given topology and choose the path between two hosts in each tree, ...
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In Proceedings of the 7th ACM/IFIP/USENIX Middleware Conference (November 2006)
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In Proceedings of the 21st USENIX Large Installation System Administration Conference (2007), pp. 1-15
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In Proceedings of the 5th ACM/USENIX Symposium on Networked Systems Design and Implementation (April 2008)
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SIGOPS Oper. Syst. Rev. In Proceedings of twenty-first ACM SIGOPS symposium on Operating systems principles, Vol. 41 (October 2007), pp. 265-278, doi:10.1145/1294261.1294287
Abstract
Power management has become increasingly necessary in large-scale datacenters to address costs and limitations in cooling or power delivery. This paper explores how to integrate power management mechanisms and policies with the virtualization technologies being actively deployed in these environments. The goals of the proposed VirtualPower approach to online power management are (i) to support the isolated and independent operation assumed by guest virtual machines (VMs) running on virtualized platforms and (ii) to make it possible to control and globally coordinate ...
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Abstract
Large-scale Internet services require a computing infrastructure that can beappropriately described as a warehouse-sized computing system. The cost ofbuilding datacenter facilities capable of delivering a given power capacity tosuch a computer can rival the recurring energy consumption costs themselves.Therefore, there are strong economic incentives to operate facilities as closeas possible to maximum capacity, so that the non-recurring facility costs canbe best amortized. That is difficult to achieve in practice because ofuncertainties in equipment power ratings and because power consumption tends tovary ...
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Abstract
Internet-based applications and their resulting multitier distributed architectures have changed the focus of design for large-scale Internet computing. Internet server applications execute in a horizontally scalable topology across hundreds or thousands of commodity servers in Internet data centers. Increasing scale and power density significantly impacts the data center's thermal properties. Effective thermal management is essential to the robustness of mission-critical applications. Internet service architectures can address multisystem resource management as well as thermal management within data centers. ...
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In DASC '06: Proceedings of the 2nd IEEE International Symposium on Dependable, Autonomic and Secure Computing (DASC'06) (2006), pp. 195-202, doi:10.1109/dasc.2006.47
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In ATEC'05: Proceedings of the USENIX Annual Technical Conference 2005 on USENIX Annual Technical Conference (2005), pp. 5-5
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In SOSP '07: Proceedings of twenty-first ACM SIGOPS symposium on Operating systems principles (2007), pp. 279-292, doi:10.1145/1294261.1294289
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In SOSP '07: Proceedings of twenty-first ACM SIGOPS symposium on Operating systems principles (2007), pp. 351-366, doi:10.1145/1294261.1294295
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In USENIX Annual Technical Conference, pp. 199-212
Abstract
This paper presents the design and implementation of Shirako, a system for on-demand leasing of shared networked resources. Shirako is a prototype of a service-oriented architecture for resource providers and consumers to negotiate access to resources over time, arbitrated by brokers. It is based on a general lease abstraction: a lease represents a contract for some quantity of a typed resource over an interval of time. Resource types have attributes that define their performance behavior and degree of isolation. <P> Shirako ...
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In 4th USENIX Symposium on Networked Systems Design & Implementation (2007), pp. 215-228
Abstract
<p> The networked and distributed systems research communities have an increasing need for “replayable” research, but our current experimentation resources fall short of satisfying this need. Replayable activities are those that can be re-executed, either as-is or in modified form, yielding new results that can be compared to previous ones. Replayability requires complete records of experiment processes and data, of course, but it also requires facilities that allow those processes to actually be examined, repeated, modified, and reused. </p> <p> We ...
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USENIX 2005 Annual Technical Conference, FREENIX Track, pp. 41-46
Abstract
We present the internals of QEMU, a fast machine emulator using an original portable dynamic translator. It emulates several CPUs (x86, PowerPC, ARM and Sparc) on several hosts (x86, PowerPC, ARM, Sparc, Alpha and MIPS). QEMU supports full system emulation in which a complete and unmodified operating system is run in a virtual machine and Linux user mode emulation where a Linux process compiled for one target CPU can be run on another CPU. ...
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9th Workshop on Hot Topics in Operating Systems (HotOS IX)
Abstract
Recent research has produced a new and perhaps dangerous technique for uniquely identifying blocks that I will call <i>compare-by-hash</i>. Using this technique, we decide whether two blocks are identical to each other by comparing their hash values, using a collision-resistant hash such as SHA-1[5]. If the hash values match, we assume the blocks are identical without further ado. Users of compare-by-hash argue that this assumption is warranted because the chance of a hash collision between any two randomly generated blocks is ...
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USENIX 2003 Annual Technical Conference, General Track
Abstract
Many objects, such as files, electronic messages, and web pages, contain overlapping content. Numerous past research projects have observed that one can compress one object relative to another one by computing the differences between the two, but these <i>delta- encoding</I> systems have almost invariably required knowledge of a specific relationship between them--most commonly, two versions using the same name at different points in time. We consider cases in which this relationship is determined dynamically, by efficiently determining when a sufficient resemblance ...
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USENIX 2004 Annual Technical Conference, General Track, pp. 59-72
Abstract
Ongoing advancements in technology lead to ever-increasing storage capacities. In spite of this, optimizing storage usage can still provide rich dividends. Several techniques based on delta-encoding and duplicate block suppression have been shown to reduce storage overheads, with varying requirements for resources such as computation and memory. We propose a new scheme for storage reduction that reduces data sizes with an effectiveness comparable to the more expensive techniques, but at a cost comparable to the faster but less effective ones. The ...
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In Proceedings of the USENIX Winter 1994 Technical Conference (JanuaryJuly--FebruaryJanuary 1994), pp. 23-32
Abstract
GLIMPSE, which stands for GLobal IMPlicit SEarch, provides indexing and query schemes for file systems. The novelty of glimpse is that it uses a very small index --- in most cases 2-4% of the size of the text --- and still allows very flexible full-text retrieval including Boolean queries, approximate matching (i.e., allowing misspelling) , and even searching for regular expressions. In a sense, glimpse extends agrep to entire file systems, while preserving most of its functionality and... ...
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In 4th USENIX Conference on File and Storage Technologies (2005), pp. 281-294
Abstract
We present TAPER, a scalable data replication protocol that synchronizes a large collection of data across multiple geographically distributed replica locations. TAPER can be applied to a broad range of systems, such as software distribution mirrors, content distribution networks, backup and recovery, and federated file systems. TAPER is designed to be bandwidth efficient, scalable and content-based, and it does not require prior knowledge of the replica state. To achieve these properties, TAPER provides: i) four pluggable redundancy elimination phases that balance ...
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OSDI '04, pp. 17-30
Abstract
We propose a method to reuse unmodified device drivers and to improve system dependability using virtual machines. We run the unmodified device driver, with its original operating system, in a virtual machine. This approach enables extensive reuse of existing and unmodified drivers, independent of the OS or device vendor, significantly reducing the barrier to building new OS endeavors. By allowing distinct device drivers to reside in separate virtual machines, this technique isolates faults caused by defective or malicious drivers, thus improving ...
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Abstract
The “VM Turntable” demonstrator at iGRID 2005 pioneered the integration of Virtual Machines (VMs) with deterministic “lightpath” network services across a MAN/WAN. The results provide for a new stage of virtualization—one for which computation is no longer localized within a data center but rather can be migrated across geographical distances, with negligible downtime, transparently to running applications and external clients. A noteworthy data point indicates that a live VM was migrated between Amsterdam, NL and San Diego, USA with just 1–2 s ...
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NSDI '05, pp. 1-11
Abstract
Migrating operating system instances across distinct physical hosts is a useful tool for administrators of data centers and clusters: It allows a clean separation between hardware and software, and facilitates fault management, load balancing, and low-level system maintenance. <P>By carrying out the majority of migration while OSes continue to run, we achieve impressive performance with minimal service downtimes; we demonstrate the migration of entire OS instances on a commodity cluster, recording service downtimes as low as 60ms. We show that ...
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Computer Architecture and High Performance Computing, 2003. Proceedings. 15th Symposium on (2003), pp. 10-18
Abstract
We reevaluate the use of adaptive compressed caching in order to improve system performance through reduction of accesses to the backing stores. We propose a new and simple adaptability policy that adjusts the compressed cache size on-the-fly, and evaluate a compressed caching system with this policy through an implementation in a widely used operating system, Linux. We also redesign compressed caching in order to provide performance improvements for all tested workloads and address the problems faced in previous works and implementations ...
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pp. 101-116
Abstract
Compressed caching uses part of the available RAM to hold pages in compressed form, effectively adding a new level to the virtual memory hierarchy. This level attempts to bridge the huge performance gap between normal (uncompressed) RAM and disk. Unfortunately, previous studies did not show a consistent benefit from the use of compressed virtual memory. In this study, we show that technology trends favor compressed virtual memory---it is attractive now, offering reduction of paging costs of... ...
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In USENIX Winter (1993), pp. 519-529
Abstract
This paper describes a method for trading off computation for disk or network I/O by using less expensive on-line compression. By using some memory to store data in compressed format, it may be possible to fit the working set of one or more large applications in relatively small memory. For working sets that are too large to fit in memory even when compressed, compression still provides a benefit by reducing bandwidth and space requirements. Overall, the effectiveness of this compression cache... ...
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USENIX 2005 Annual Technical Conference, General Track, pp. 237-250
Abstract
Applications that use large data sets frequently exhibit poor performance because the size of their working set exceeds the real memory, causing excess page faults, and ultimately exhibit thrashing behavior. <P> This paper describes a memory compression solution to this problem that adapts the allocation of real memory between uncompressed and compressed pages and also manages fragmentation without user involvement. The system manages its resources dynamically on the basis of the varying demands of each application ...
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Computer Systems, Vol. 2, No. 3. (1984), pp. 181-197
Abstract
A reimplementation of the UNIX file system is described. The reimplementation provides substantially higher throughput rates by using more flexible allocation policies that allow better locality of reference and can be adapted to a wide range of peripheral and processor characteristics. The new file system clusters data that is sequentially accessed and provides two block sizes to allow fast access to large files while not wasting large amounts of space for small files. File access rates of up... ...
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In Proceedings of the USENIX Winter 1994 Technical Conference (JanuaryJuly--FebruaryJanuary 1994), pp. 1-10
Abstract
We present a tool, called sif, for finding all similar files in a large file system. Files are considered similar if they have significant number of common pieces, even if they are very different otherwise. For example, one file may be contained, possibly with some changes, in another file, or a file may be a reorganization of another file. The running time for finding all groups of similar files, even for as little as 25% similarity, is on the order of 500MB to 1GB an ...
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SIGOPS Oper. Syst. Rev. In SOSP '97: Proceedings of the sixteenth ACM symposium on Operating systems principles, Vol. 31, No. 5. (October 1997), pp. 143-156, doi:10.1145/268998.266672
Abstract
An abstract is not available. ...
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In International Conference on Architectural Support for Programming Languages and Operating Systems (October 1996)
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Micro, IEEE, Vol. 23, No. 2. (2003), pp. 22-28
Abstract
Amenable to extensive parallelization, Google's web search application lets different queries run on different processors and, by partitioning the overall index, also lets a single query use multiple processors. to handle this workload, Googless architecture features clusters of more than 15,000 commodity-class PCs with fault tolerant software. This architecture achieves superior performance at a fraction of the cost of a system built from fewer, but more expensive, high-end servers. ...
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In Sixth Symposium on Operating Systems Design and Implementation, pp. 273-288
Abstract
This paper shows how to use model checking to find serious errors in file systems. Model checking is a formal verification technique tuned for finding corner-case errors by comprehensively exploring the state spaces defined by a system. File systems have two dynamics that make them attractive for such an approach. First, their errors are some of the most serious, since they can destroy persistent data and lead to unrecoverable corruption. Second, traditional testing needs an impractical, exponential number of test cases ...
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OSDI '02
Abstract
Many system errors do not emerge unless some intricate sequence of events occurs. In practice, this means that most systems have errors that only trigger after days or weeks of execution. Model checking <a H REF="full_papers/musuvathi/musuvathi_html/node18.html#clarke:modelchec king">4</a> is an effective way to find such subtle errors. It takes a simplified description of the code and exhaustively tests it on all inputs, using techniques to explore vast state spaces efficiently. Unfortunately, while model checking systems code would be wonderful, it is almost ...
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NSDI '04, pp. 155-168
Abstract
Network protocols must work. The effects of protocol specification or implementation errors range from reduced performance, to security breaches, to bringing down entire networks. However, network protocols are difficult to test due to the exponential size of the state space they define. Ideally, a protocol implementation must be validated against all possible events (packet arrivals, packet losses, timeouts, etc.) in all possible protocol states. Conventional means of testing can explore only a minute fraction of these possible combinations. <P> This paper ...
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In Proceedings of the 11th {ACM} {SIGOPS} European Workshop ({EW} 2004) (2004), pp. 126-130
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IEEE Journal of Selected Areas in Communications, Vol. 14, No. 7. (1996), pp. 1280-1297
Abstract
Support for multimedia applications by general purpose computing platforms has been the subject of considerable research. Much of this work is based on an evolutionary strategy in which small changes to existing systems are made. The approach adopted here is to start ab initio with no backward compatibility constraints. This leads to a novel structure for an operating system. The structure aims to decouple applications from one another and to provide multiplexing of all resources, not just the... ...
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(2004)
Abstract
Virtual machine monitors (VMMs) have enjoyed a resurgence in popularity, since VMMs can help to solve di#cult systems problems like migration, fault tolerance, code sandboxing, intrusion detection, and debugging. Recently, several researchers have proposed novel applications of virtual machine technology, such as Internet Suspend/Resume [25, 31] and transparent OS-level rollback and replay [13]. Unfortunately, current VMMs do not export enough functionality to budding developers of such... ...
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In SOSP '05: Proceedings of the twentieth ACM symposium on Operating systems principles (2005), pp. 1-16
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In USENIX Annual Technical Conference (May 2006), pp. 15-28
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OSDI '04, pp. 61-76
Abstract
Operator mistakes are a significant source of unavailability in modern Internet services. In this paper, we first characterize these mistakes by performing an extensive set of experiments using human operators and a realistic three-tier auction service. The mistakes we observed range from software misconfiguration, to fault misdiagnosis, to incorrect software restarts. We next propose to validate operator actions before they are made visible to the rest of the system. We demonstrate how to accomplish this task via ...
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OSDI '02
Abstract
VMware ESX Server is a thin software layer designed to multiplex hardware resources efficiently among virtual machines running unmodified commodity operating systems. This paper introduces several novel ESX Server mechanisms and policies for managing memory. A <em>ballooning</em> technique reclaims the pages considered least valuable by the operating system running in a virtual machine. An <em>idle memory tax</em> achieves efficient memory utilization while maintaining performance isolation guarantees. <em>Content-based page sharing</em> and <em>hot I/O page remapping</em> exploit transparent page ...
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HotOS X, Tenth Workshop on Hot Topics in Operating Systems, pp. 1-11
Abstract
OS virtualization is drastically changing the face of system administration for large computer installations such as commercial datacenters and scientific clusters. A recent report by Gartner predicts that commercial use of virtualization will triple over the five year period beginning in 2004. While it is commonly held that OS virtualization improves the utility, manageability, and scalability of large-scale environments, we believe that it is not sufficient in itself. In this paper we argue that the next key challenge facing these environments ...
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(2004)
Abstract
We present a next-generation architecture that addresses problems of dependability, maintainability, and manageability of I/O devices and their software drivers on the PC platform. Our architecture resolves both hardware and software issues, exploiting emerging hardware features to improve device safety. Our high-performance implementation, based on the Xen virtual machine monitor, provides an immediate transition opportunity for today's systems. ...
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