578 research outputs found
PrismDB: Read-aware Log-structured Merge Trees for Heterogeneous Storage
In recent years, emerging hardware storage technologies have focused on
divergent goals: better performance or lower cost-per-bit of storage.
Correspondingly, data systems that employ these new technologies are optimized
either to be fast (but expensive) or cheap (but slow). We take a different
approach: by combining multiple tiers of fast and low-cost storage technologies
within the same system, we can achieve a Pareto-efficient balance between
performance and cost-per-bit.
This paper presents the design and implementation of PrismDB, a novel
log-structured merge tree based key-value store that exploits a full spectrum
of heterogeneous storage technologies (from 3D XPoint to QLC NAND). We
introduce the notion of "read-awareness" to log-structured merge trees, which
allows hot objects to be pinned to faster storage, achieving better tiering and
hot-cold separation of objects. Compared to the standard use of RocksDB on
flash in datacenters today, PrismDB's average throughput on heterogeneous
storage is 2.3 faster and its tail latency is more than an order of
magnitude better, using hardware than is half the cost
A Survey and Evaluation of Android-Based Malware Evasion Techniques and Detection Frameworks
Android platform security is an active area of research where malware detection techniques continuously evolve to identify novel malware and improve the timely and accurate detection of existing malware. Adversaries are constantly in charge of employing innovative techniques to avoid or prolong malware detection effectively. Past studies have shown that malware detection systems are susceptible to evasion attacks where adversaries can successfully bypass the existing security defenses and deliver the malware to the target system without being detected. The evolution of escape-resistant systems is an open research problem. This paper presents a detailed taxonomy and evaluation of Android-based malware evasion techniques deployed to circumvent malware detection. The study characterizes such evasion techniques into two broad categories, polymorphism and metamorphism, and analyses techniques used for stealth malware detection based on the malware’s unique characteristics. Furthermore, the article also presents a qualitative and systematic comparison of evasion detection frameworks and their detection methodologies for Android-based malware. Finally, the survey discusses open-ended questions and potential future directions for continued research in mobile malware detection
ATP: a Datacenter Approximate Transmission Protocol
Many datacenter applications such as machine learning and streaming systems
do not need the complete set of data to perform their computation. Current
approximate applications in datacenters run on a reliable network layer like
TCP. To improve performance, they either let sender select a subset of data and
transmit them to the receiver or transmit all the data and let receiver drop
some of them. These approaches are network oblivious and unnecessarily transmit
more data, affecting both application runtime and network bandwidth usage. On
the other hand, running approximate application on a lossy network with UDP
cannot guarantee the accuracy of application computation. We propose to run
approximate applications on a lossy network and to allow packet loss in a
controlled manner. Specifically, we designed a new network protocol called
Approximate Transmission Protocol, or ATP, for datacenter approximate
applications. ATP opportunistically exploits available network bandwidth as
much as possible, while performing a loss-based rate control algorithm to avoid
bandwidth waste and re-transmission. It also ensures bandwidth fair sharing
across flows and improves accurate applications' performance by leaving more
switch buffer space to accurate flows. We evaluated ATP with both simulation
and real implementation using two macro-benchmarks and two real applications,
Apache Kafka and Flink. Our evaluation results show that ATP reduces
application runtime by 13.9% to 74.6% compared to a TCP-based solution that
drops packets at sender, and it improves accuracy by up to 94.0% compared to
UDP
Defense and Attack Techniques against File-based TOCTOU Vulnerabilities: a Systematic Review
File-based Time-of-Check to Time-of-Use (TOCTOU) race conditions are a well-known type of security vulnerability. A wide variety of techniques have been proposed to detect, mitigate, avoid, and exploit these vulnerabilities over the past 35 years. However, despite these research efforts, TOCTOU vulnerabilities remain unsolved due to their non-deterministic nature and the particularities of the different filesystems involved in running vulnerable programs, especially in Unix-like operating system environments. In this paper, we present a systematic literature review on defense and attack techniques related to the file-based TOCTOU vulnerability. We apply a reproducible methodology to search, filter, and analyze the most relevant research proposals to define a global and understandable vision of existing solutions. The results of this analysis are finally used to discuss future research directions that can be explored to move towards a universal solution to this type of vulnerability. Autho
On Evaluating Commercial Cloud Services: A Systematic Review
Background: Cloud Computing is increasingly booming in industry with many
competing providers and services. Accordingly, evaluation of commercial Cloud
services is necessary. However, the existing evaluation studies are relatively
chaotic. There exists tremendous confusion and gap between practices and theory
about Cloud services evaluation. Aim: To facilitate relieving the
aforementioned chaos, this work aims to synthesize the existing evaluation
implementations to outline the state-of-the-practice and also identify research
opportunities in Cloud services evaluation. Method: Based on a conceptual
evaluation model comprising six steps, the Systematic Literature Review (SLR)
method was employed to collect relevant evidence to investigate the Cloud
services evaluation step by step. Results: This SLR identified 82 relevant
evaluation studies. The overall data collected from these studies essentially
represent the current practical landscape of implementing Cloud services
evaluation, and in turn can be reused to facilitate future evaluation work.
Conclusions: Evaluation of commercial Cloud services has become a world-wide
research topic. Some of the findings of this SLR identify several research gaps
in the area of Cloud services evaluation (e.g., the Elasticity and Security
evaluation of commercial Cloud services could be a long-term challenge), while
some other findings suggest the trend of applying commercial Cloud services
(e.g., compared with PaaS, IaaS seems more suitable for customers and is
particularly important in industry). This SLR study itself also confirms some
previous experiences and reveals new Evidence-Based Software Engineering (EBSE)
lessons
Distributed Multi-writer Multi-reader Atomic Register with Optimistically Fast Read and Write
A distributed multi-writer multi-reader (MWMR) atomic register is an
important primitive that enables a wide range of distributed algorithms. Hence,
improving its performance can have large-scale consequences. Since the seminal
work of ABD emulation in the message-passing networks [JACM '95], many
researchers study fast implementations of atomic registers under various
conditions. "Fast" means that a read or a write can be completed with 1
round-trip time (RTT), by contacting a simple majority. In this work, we
explore an atomic register with optimal resilience and "optimistically fast"
read and write operations. That is, both operations can be fast if there is no
concurrent write.
This paper has three contributions: (i) We present Gus, the emulation of an
MWMR atomic register with optimal resilience and optimistically fast reads and
writes when there are up to 5 nodes; (ii) We show that when there are > 5
nodes, it is impossible to emulate an MWMR atomic register with both
properties; and (iii) We implement Gus in the framework of EPaxos and Gryff,
and show that Gus provides lower tail latency than state-of-the-art systems
such as EPaxos, Gryff, Giza, and Tempo under various workloads in the context
of geo-replicated object storage systems
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