1 问题描述 HDFS在机器断电或意外崩溃的情况下,有可能出现正在写的数据(例如保存在DataNode内存的数据等)丢失的问题.再次重启HDFS后,发现hdfs无法启动,查看日志后发现,一直处于安全模式. 2 原因分析 出现前面提到的问题主要原因是客户端写入的数据没有及时保存到磁盘中,从而导致数据丢失:又因为数据块丢失达到一定的比率,导致hdfs启动进入安全模式. 为了弄清楚导致安全模式的原因,下面主要对hdfs安全模式和如何退出安全模式进行分析. 2.1 安全模式 当 hdfs的NameNod…

来自:http://centoshowtos.org/hadoop/fix-corrupt-blocks-on-hdfs/ How do I know if my hadoop hdfs filesystem has corrupt blocks, and how do I fix it? The easiest way to determine this is to run an fsck on the filesystem. If you have setup your hadoop env…

In this lesson we'll use prettier and lint-staged to run prettier only on files that have been changed and committed to git. This will allow you to prettify files as you change them, and prevent massive lint only git check ins. Install: npm i husky l…

If you've found yourself here, I'm guessing that you're getting Assembly - CSharp - Editor - first pass.dll error message and want to find an effective solution to fix this error. You should know for sure that you have to fix this error ASAP, otherwi…

简介 HDFS(Hadoop Distributed File System )Hadoop分布式文件系统.是根据google发表的论文翻版的.论文为GFS(Google File System)Google 文件系统(中文,英文). HDFS有很多特点: ① 保存多个副本,且提供容错机制,副本丢失或宕机自动恢复.默认存3份. ② 运行在廉价的机器上. ③ 适合大数据的处理.多大?多小?HDFS默认会将文件分割成block,64M为1个block.然后将block按键值对存储在HDFS上,并将键…

Hadoop集群-HDFS集群中大数据运维常用的命令总结 作者:尹正杰 版权声明:原创作品,谢绝转载!否则将追究法律责任. 本篇博客会简单涉及到滚动编辑,融合镜像文件,目录的空间配额等运维操作简介.话不多少,直接上命令便于以后查看.   一.查看hadf的帮助信息 [yinzhengjie@s101 ~]$ hdfs Usage: hdfs [--config confdir] [--loglevel loglevel] COMMAND where COMMAND is one of: dfs…

HDFS Architecture HDFS Architecture(HDFS 架构) Introduction(简介) Assumptions and Goals(假设和目标) Hardware Failure(硬件失效是常态) Streaming Data Access(支持流式访问) Large Data Sets(大数据集) Simple Coherency Model(简单一致性模型) "Moving Computation is Cheaper than Moving Data&q…

HDFS Architecture Introduction The Hadoop Distributed File System (HDFS) is a distributed file system designed to run on commodity hardware. It has many similarities with existing distributed file systems. However, the differences from other distribu…

The Hadoop Distributed File System has been great in providing a cloud-type file system. It is robust (when administered correctly :-)) and highly scalable. However, one of the main drawbacks of HDFS is that each piece of data is replicated in three…

HDFS Architecture HDFS Architecture(HDFS 架构) Introduction(简介) Assumptions and Goals(假设和目标) Hardware Failure(硬件失效是常态) Streaming Data Access(支持流式访问) Large Data Sets(大数据集) Simple Coherency Model(简单一致性模型) “Moving Computation is Cheaper than Moving Data”(…