Results 11 - 20
of
41
Applications know best: Performance-driven memory overcommit with ginkgo
- In IEEE Conf. on Cloud Computing Technology and Science (CloudCom
, 2011
"... Abstract—Memory overcommitment enables cloud providers to host more virtual machines on a single physical server, exploiting spare CPU and I/O capacity when physical memory becomes the bottleneck for virtual machine deployment. However, overcommiting memory can also cause noticeable application perf ..."
Abstract
-
Cited by 7 (0 self)
- Add to MetaCart
(Show Context)
Abstract—Memory overcommitment enables cloud providers to host more virtual machines on a single physical server, exploiting spare CPU and I/O capacity when physical memory becomes the bottleneck for virtual machine deployment. However, overcommiting memory can also cause noticeable application performance degradation. We present Ginkgo, a policy frame-work for overcomitting memory in an informed and automated fashion. By directly correlating application-level performance to memory, Ginkgo automates the redistribution of scarce memory across all virtual machines, satisfying performance and capacity constraints. Ginkgo also achieves memory gains for traditionally fixed-size Java applications by coordinating the redistribution of available memory with the activities of the Java Virtual Machine heap. When compared to a non-overcommited system, Ginkgo runs the DayTrader 2.0 and SPECWeb 2009 benchmarks with the same number of virtual machines while saving up to 73% (50 % omitting free space) of a physical server’s memory while keeping application performance degradation within 7%. I.
Improving data center resource management, deployment, and availability with virtualization
, 2009
"... The increasing demand for storage and computation has driven the growth of large data centers–the massive server farms that run many of today’s Internet and business applications. A data center can comprise many thousands of servers and can use as much energy as a small city. The massive amounts of ..."
Abstract
-
Cited by 6 (0 self)
- Add to MetaCart
The increasing demand for storage and computation has driven the growth of large data centers–the massive server farms that run many of today’s Internet and business applications. A data center can comprise many thousands of servers and can use as much energy as a small city. The massive amounts of computation power required to drive these systems results in many challenging and interesting distributed systems and resource management problems. In this thesis I investigate challenges related to data centers, with a particular emphasis on how new virtualization technologies can be used to simplify deployment, improve resource efficiency, and reduce the cost of reliability. I first study problems that relate the initial capacity planning required when deploying applications into a virtualized data center. I demonstrate how models iv of virtualization overheads can be utilized to accurately predict the resource needs of virtualized applications, allowing them to be smoothly transitioned into a data center. I next study how memory similarity can be used to guide placement when
Gang Migration of Virtual Machines using Cluster-wide Deduplication
"... Abstract—Gang migration refers to the simultaneous live migration of multiple Virtual Machines (VMs) from one set of physical machines to another in response to events such as load spikes and imminent failures. Gang migration generates a large volume of network traffic and can overload the core netw ..."
Abstract
-
Cited by 4 (0 self)
- Add to MetaCart
(Show Context)
Abstract—Gang migration refers to the simultaneous live migration of multiple Virtual Machines (VMs) from one set of physical machines to another in response to events such as load spikes and imminent failures. Gang migration generates a large volume of network traffic and can overload the core network links and switches in a datacenter. In this paper, we present an approach to reduce the network overhead of gang migration using global deduplication (GMGD). GMGD identifies and eliminates the retransmission of duplicate memory pages among VMs runningon multiplephysical machines inthe cluster. We describe the design, implementation and evaluation of a GMGD prototype using QEMU/KVM VMs. Evaluations on a 30node Gigabit Ethernet cluster having 10GigE core links shows that GMGD can reduce the network traffic on core links by up to 65 % and the total migration time of VMs by up to 42 % when compared to the default migration technique in QEMU/KVM. Furthermore, GMGD has a smaller adverse performance impact on network-bound applications. I.
A New Buffer Cache Design Exploiting Both Temporal and Content Localities.
- In 2010 International Conference on Distributed Computing Systems,
, 2010
"... ..."
(Show Context)
Whispers in the Hyper-space: High-bandwidth and Reliable Covert Channel Attacks inside the Cloud
"... Abstract—Privacy and information security in general are major concerns that impede enterprise adaptation of shared or public cloud computing. Specifically, the concern of virtual machine (VM) physical co-residency stems from the threat that hostile tenants can leverage various forms of side channel ..."
Abstract
-
Cited by 3 (0 self)
- Add to MetaCart
Abstract—Privacy and information security in general are major concerns that impede enterprise adaptation of shared or public cloud computing. Specifically, the concern of virtual machine (VM) physical co-residency stems from the threat that hostile tenants can leverage various forms of side channels (such as cache covert channels) to exfiltrate sensitive information of victims on the same physical system. However, on virtualized x86 systems, covert channel attacks have not yet proven to be practical, and thus the threat is widely considered a “potential risk”. In this paper, we present a novel covert channel attack that is capable of high-bandwidth and reliable data transmission in the cloud. We first study the application of existing cache channel techniques in a virtualized environment, and uncover their major insufficiency and difficulties. We then overcome these obstacles by (1) redesigning a pure timing-based data transmission scheme, and (2) exploiting the memory bus as a high-bandwidth covert channel medium. We further design and implement a robust communication protocol, and demonstrate realistic covert chan-nel attacks on various virtualized x86 systems. Our experimental results show that covert channels do pose serious threats to information security in the cloud. Finally, we discuss our insights on covert channel mitigation in virtualized environments. Index Terms—Cloud, Covert channel, Network security. I.
A Survey and Classification of Storage Deduplication Systems
"... The automatic elimination of duplicate data in a storage system, commonly known as deduplication, is increasingly accepted as an effective technique to reduce storage costs. Thus, it has been applied to different storage types, including archives and backups, primary storage, within solid-state driv ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
The automatic elimination of duplicate data in a storage system, commonly known as deduplication, is increasingly accepted as an effective technique to reduce storage costs. Thus, it has been applied to different storage types, including archives and backups, primary storage, within solid-state drives, and even to random access memory. Although the general approach to deduplication is shared by all storage types, each poses specific challenges and leads to different trade-offs and solutions. This diversity is often misunderstood, thus underestimating the relevance of new research and development. The first contribution of this article is a classification of deduplication systems according to six criteria that correspond to key design decisions: granularity, locality, timing, indexing, technique, and scope. This classification identifies and describes the different approaches used for each of them. As a second contribution, we describe which combinations of these design decisions have been proposed and found more useful for challenges in each storage type. Finally, outstanding research challenges and unexplored design points are identified and discussed.
SECURITY CHALLENGES WITH VIRTUALIZATION
"... Virtualização é uma palavra em voga no mundo das tecnologias de informação. Com a promessa de reduzir o constante crescimento das infra-estruturas informáticas dentro de um centro de processamento de dados, aliado a outros aspectos importantes como disponi-bilidade e escalabilidade, as tecnologias d ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
Virtualização é uma palavra em voga no mundo das tecnologias de informação. Com a promessa de reduzir o constante crescimento das infra-estruturas informáticas dentro de um centro de processamento de dados, aliado a outros aspectos importantes como disponi-bilidade e escalabilidade, as tecnologias de virtualização têm vindo a ganhar popularidade, não só entre os profissionais de tecnologias de informação mas também administradores e directores. No entanto, o aumento da adopção do uso desta tecnologia expõe o sistema a novas preocupações de segurança que normalmente são negligenciadas. Esta tese apresenta o estado da arte das soluções actualmente mais usadas de virtualização de servidores e também um estudo literário dos vários problemas de segurança das tecno-logias de virtualização. Estes problemas não são específicos em termos de produto, e são abordados no âmbito de tecnologias de virtualização. No entanto, nesta tese é feita uma análise de vulnerabilidades de duas das mais conhecidas soluções de virtualização: VM-ware EXS e Xen. No final, são descritas algumas soluções para melhorar a segurança de acesso a banco online e de comercio electrónico, usando virtualização.
Singleton: System-wide Page Deduplication in Virtual Environments
"... ABSTRACT We consider the problem of providing memory-management in hypervisors and propose Singleton, a KVM-based systemwide page deduplication solution to increase memory usage efficiency. Specifically, we address the problem of doublecaching that occurs in KVM-the same disk blocks are cached at b ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
(Show Context)
ABSTRACT We consider the problem of providing memory-management in hypervisors and propose Singleton, a KVM-based systemwide page deduplication solution to increase memory usage efficiency. Specifically, we address the problem of doublecaching that occurs in KVM-the same disk blocks are cached at both the host(hypervisor) and the guest(VM) page-caches. Singleton's main components are identical-page sharing across guest virtual machines and an implementation of an exclusivecache for the host and guest page-cache hierarchy. We use and improve KSM-Kernel SamePage Merging to identify and share pages across guest virtual machines. We utilize guest memory-snapshots to scrub the host page-cache and maintain a single copy of a page across the host and the guests. Singleton operates on a completely black-box assumption-we do not modify the guest or assume anything about it's behaviour. We show that conventional operating system cache management techniques are sub-optimal for virtual environments, and how Singleton supplements and improves the existing Linux kernel memory management mechanisms. Singleton is able to improve the utilization of the host cache by reducing its size(by upto an order of magnitude), and increasing the cache-hit ratio(by factor of 2x). This translates into better VM performance(40% faster I/O). Singleton's unified page deduplication and host cache scrubbing is able to reclaim large amounts of memory and facilitates higher levels of memory overcommitment. The optimizations to page deduplication we have implemented keep the overhead down to less than 20% CPU utilization.
Inter-rack Live Migration of Multiple Virtual Machines
"... Within datacenters, often multiple virtual machines (VMs) need to be live migrated simultaneously for various reasons such as maintenance, power savings, and load balancing. Such mass simultaneous live migration of multiple VMs can trigger large data transfers across the core network links and switc ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
(Show Context)
Within datacenters, often multiple virtual machines (VMs) need to be live migrated simultaneously for various reasons such as maintenance, power savings, and load balancing. Such mass simultaneous live migration of multiple VMs can trigger large data transfers across the core network links and switches, and negatively affect the cluster-wide performance of network-bound applications. In this paper, we present a distributed system for inter-rack live migration (IRLM), i.e., parallel live migration of multiple VMs across racks. The key performance objective of IRLM is to reduce the traffic load on the core network links during mass VM migration through distributed deduplication of VMs ’ memory images. We present an initial prototype of IRLM that migrates multiple QEMU/KVM VMs within a Gigabit Ethernet cluster with 10GigE core links. We also present preliminary evaluation on a small testbed having 6 hosts per rack and 4 VMs per host. Our evaluations show that, compared to the default live migration technique in QEMU/KVM, IRLM reduces the network traffic on core links by up to 44 % and the total migration time by up to 26%. We also demonstrate that network-bound applications experience a smaller degradation during migration using IRLM. Categories andSubjectDescriptors
Group-based memory deduplication for virtualized clouds
- In 6th Workshop on Virtualization in High-Performance Cloud Computing, VHPC 2011
, 2011
"... Abstract. In virtualized clouds, machine memory is known as a resource that primarily limits consolidation level due to the expensive cost of hardware extension and power consumption. To address this limitation, various memory deduplication techniques have been proposed to increase available machin ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
(Show Context)
Abstract. In virtualized clouds, machine memory is known as a resource that primarily limits consolidation level due to the expensive cost of hardware extension and power consumption. To address this limitation, various memory deduplication techniques have been proposed to increase available machine memory by eliminating memory redundancy. Existing memory deduplication techniques, however, lack isolation support, which is a crucial factor of cloud quality of service and trustworthiness. This paper presents a group-based memory deduplication scheme that ensures isolation between customer groups colocated in a physical machine. In addition to isolation support, our scheme enables per-group customization of memory deduplication according to each group's memory demand and workload characteristic.
