The Hadoop Distributed File System (HDFS) is the storage layer for Apache Hadoop ecosystem, persisting large data sets across multiple machines. However, the overall storage capacity is limited since the metadata is stored in-memory on a single server, called the NameNode. The heap size of the NameNode restricts the number of data files and addressable blocks persisted in the file system. The H...

MapReduce is a powerful distributed processing model for large datasets. Hadoop is an open source framework and implementation of MapReduce. Hadoop distributed file system (HDFS) has become very popular to build large scale and high performance distributed data processing system. HDFS is designed mainly to handle big size files, so the processing of massive small files is a challenge in native ...

This study determined the molecular mechanisms of tocotrienol-rich fraction (TRF) in preventing cellular senescence of human diploid fibroblasts (HDFs). Primary culture of HDFs at various passages were incubated with 0.5 mg/mL TRF for 24 h. Telomere shortening with decreased telomerase activity was observed in senescent HDFs while the levels of damaged DNA and number of cells in G(0)/G(1) phase...

As an open source cloud storage scheme, HDFS is used by more and more large enterprises and researchers, and is actually applied to many cloud computing systems to deal with huge amounts of data. HDFS has many advantages, but there are some problems such as NameNode single point of failure, small file problem, hot issues, etc. For HDFS hot issues, this paper proposes a dynamic Replication mecha...

Piper betle (PB) is a traditional medicine that is widely used to treat different diseases around Asian region. The leaf extracts contain various bioactive compounds, which were reported to have antidiabetic, antibacterial, anti-inflammatory, antioxidant, and anticancer effects. In this study, the effect of PB aqueous extracts on replicative senescent human diploid fibroblasts (HDFs) was invest...

Few cloud storage systems can handle random read accesses efficiently. In this paper, we present a RAMCloud Storage System, RCSS, to enable efficient random read accesses in cloud environments. Based on the Hadoop Distributed File System (HDFS), RCSS integrates the available memory resources in an HDFS cluster to form a cloud storage system, which backs up all data on HDFS-managed disks, and fe...

Handling high concurrency is a critical issue in almost all internet services. A web server is a perfect example where a large amount of concurrent users are served by managing limited resources. There has been number of different architectures proposed to optimize the resource usage and maximize the throughput in such applications. Thread-per-request model and event-driven model are two heavil...

The ability to take snapshots is an essential functionality of any file system, as snapshots enable system administrators to perform data backup and recovery in case of failure. We present a low-overhead snapshot solution for HDFS, a popular distributed file system for large clusters of commodity servers. Our solution obviates the need for complex distributed snapshot algorithms, by taking adva...

TheHadoopDistributed File System (HDFS) is designed to run on commodity hardware and can be used as a stand-alone general purpose distributed file system (Hdfs user guide, 2008). It provides the ability to access bulk data with high I/O throughput. As a result, this system is suitable for applications that have large I/O data sets. However, the performance of HDFS decreases dramatically when ha...

The present study was designed to determine the radioprotective effects of Malaysian Gelam honey on gene expression and enzyme activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) of human diploid fibroblasts (HDFs) subjected to gamma-irradiation. Six groups of HDFs were studied: untreated control, irradiated HDFs, Gelam honey-treated HDFs and HDF treated with...