We present the first comprehensive study of application-level crash-consistency protocols built atop modern file systems. find that applications use complex update to persist state, and correctness these is highly dependent on subtle behaviors underlying system, which we term persistence properties. develop a tool named BOB empirically tests properties, it demonstrate properties vary widely among six popular Linux build framework ALICE analyzes application finds crash vulnerabilities, i.e.,...

Data structures for non-volatile memories have to be designed such that they can atomically modified using transactions. Existing atomicity methods require data copied in the critical path which significantly increases latency of These overheads are further amplified transactions on byte-addressable persistent where often byte ranges structure updates smaller compared granularity at efficiently and logged. We propose Kamino-Tx provides a new way perform transactional (NVM) without requiring...

Modern distributed storage systems employ complex protocols to update replicated data. In this paper, we study whether such work correctly in the presence of correlated crashes. We find that correctness hinges on how local file-system state is updated by each replica system. build PACE, a framework systematically generates and explores persistent states can occur execution. PACE uses set generic rules effectively prune space, reducing checking time from days hours some cases. apply eight...

Recent research has shown that applications often incorrectly implement crash consistency. We present the Crash-Consistent File System (ccfs), a file system improves correctness of application-level consistency protocols while maintaining high performance. A key idea in ccfs is abstraction stream . Within stream, updates are committed program order, improving correctness; across streams, there no ordering restrictions, enabling scheduling flexibility and empirically demonstrate running atop...

We analyze how modern distributed storage systems behave in the presence of file-system faults such as data corruption and read write errors. characterize eight popular uncover numerous problems related to fault tolerance. find that do not consistently use redundancy recover from faults: a single can cause catastrophic outcomes loss, corruption, unavailability. also above arise due fundamental handling are common across many systems. Our results have implications for design next-generation...

We introduce BOURBON, a log-structured merge (LSM) tree that utilizes machine learning to provide fast lookups. base the design and implementation of BOURBON on empirically-grounded principles we derive through careful analysis LSM design. employs greedy piecewise linear regression learn key distributions, enabling lookup with minimal computation, applies cost-benefit strategy decide when will be worthwhile. Through series experiments both synthetic real-world datasets, show improves...

Rethinking the fundamental abstractions of file system.

We introduce SplitFt, a new fault-tolerance approach for storage-centric applications in disaggregated data centers. SplitFt uses novel split architecture, where large writes are directly performed on the underlying storage system, while small made fault-tolerant within compute layer. The architecture enables to achieve strong durability guarantees without compromising performance. makes using abstraction called near-compute logs or Ncl, which leverages underutilized memory remote nodes log...

Bookazor is an appointment booking and scheduling web-based application which used for appointments in the streams of parlor, hospitals architects within a defined geographic area. This streamlined ionic basis. It open source SDK hybrid mobile development. uses technologies like CSS, HTML, JavaScript. Firebase plays vital role fetching data that helps to enhance development effectively. provides functionalities analytics, database, messaging, crash reporting focusing users. The system...

We introduce protocol-aware recovery (P ar ), a new approach that exploits protocol-specific knowledge to correctly recover from storage faults in distributed systems. demonstrate the efficacy of P through design and implementation <underline>c</underline>orruption-<underline>t</underline>olerant <underline>r</underline>ep<underline>l</underline>ication (C trl mechanism specific replicated state machine (RSM) experimentally show C versions two...

We introduce situation-aware updates and crash recovery (SAUCR), a new approach to performing replicated data in distributed system. SAUCR adapts the update protocol current situation: with many nodes up, buffers memory; when failures arise, flushes disk. This situation-awareness enables achieve high performance while offering strong durability availability guarantees. implement prototype of ZooKeeper. Through rigorous testing, we demonstrate that significantly improves compared systems...

We introduce consistency-aware durability or C ad , a new approach to in distributed storage that enables strong consistency while delivering high performance. demonstrate the efficacy of this by designing cross-client monotonic reads novel and property provides across failures sessions leader-based systems; such can be particularly beneficial geo-distributed edge-computing scenarios. build O rca modified version ZooKeeper implements reads. experimentally show closely matching performance...

The reading and writing of data, one the most fundamental aspects any Von Neumann computer, is surprisingly subtle full nuance. For example, consider access to a shared memory in system with multiple processors. While simple intuitive approach known as strong consistency easiest for programmers understand, many weaker models are widespread use (e.g., x86 total store ordering); such approaches improve performance, but at cost making reasoning about behavior more complex error-prone....

Do some storage interfaces enable higher performance than others? Can one identify and exploit such to realize high in systems? This paper answers these questions the affirmative by identifying nil-externality, a property of interfaces. A nil-externalizing (nilext) interface may modify state within system but does not externalize its effects or immediately outside world. As result, can apply nilext operations lazily, improving performance.

Shared logs offer linearizable total order across storage shards. However, they enforce this eagerly upon ingestion, leading to high latencies. We observe that in many modern shared-log applications, while ordering is necessary, it not required when ingesting data but only later consumed. Further, readers are naturally decoupled time from writers these applications. Based on insight, we propose LazyLog, a novel shared log abstraction. LazyLog lazily binds records (across shards) global...

Modern datacenter infrastructures are increasingly architected as a cluster of loosely coupled services. The states typically maintained in logically centralized, strongly consistent data store (e.g., ZooKeeper, Chubby and etcd), while the services learn about evolving state by reading from store, or via stream notifications. However, it is challenging to ensure correct, even presence failures, networking issues, inherent asynchrony distributed system. In this paper, we identify that partial...