Replica Documents

Read the file & http: //www.aliyun.com/zixun/aggregation/37954.html "> nbsp; read the file internal working mechanism see below: The client calls FileSystem object (corresponding to the HDFS file system, call DistributedFileSystem object) Open () method to open the file (ie the first step in the diagram), DistributedFileSyst ...

MongoDB company formerly known as 10gen, founded in 2007, in 2013 received a sum of 231 million U.S. dollars in financing, the company's market value has been increased to 1 billion U.S. dollar level, this height is well-known open source company Red Hat (founded in 1993) 20 's struggle results. High-performance, easy to expand has been the foothold of the MongoDB, while the specification of documents and interfaces to make it more popular with users, this point from the analysis of the results of Db-engines's score is not difficult to see-just 1 years, MongoDB finished the 7th ...

Hadoop 2.3.0 has been released, the biggest highlight of which is centralized cache management (HDFS). This function is very helpful to improve the execution efficiency and real-time performance of Hadoop system and the upper application. This paper discusses this function from three aspects: principle, architecture and code analysis. Mainly solved the problem What users can according to their own logic to specify some frequently used data or high-priority tasks corresponding to the data, so that they are not resident in memory and Amoy ...

In mailbox rapid expansion process, one of the performance problems is the MongoDB database level write lock, the time spent in the lock waiting process, directly reflects the user's use of the service process delay. To address this long-standing problem, we decided to migrate a common set of MongoDB (storing mail-related data) to a separate cluster. According to our inference, this will reduce the lock latency by 50%, and we can add more fragments, and we expect to be able to optimize and manage different types of data independently. We start from Mon ...

1. The introduction of the Hadoop Distributed File System (HDFS) is a distributed file system designed to be used on common hardware devices. It has many similarities to existing distributed file systems, but it is quite different from these file systems. HDFS is highly fault-tolerant and is designed to be deployed on inexpensive hardware. HDFS provides high throughput for application data and applies to large dataset applications. HDFs opens up some POSIX-required interfaces that allow streaming access to file system data. HDFS was originally for AP ...

The problem arises in the data cluster number of nodes storage disk size is different, resulting in a period of time after the small capacity of the disk space is tight. In fact, the early configuration of the disk using the storage strategy, you can solve the problem, some networks to say that this strategy is invalid, and then hadoop2.0.1 this version is valid, the version applies to CHD4.6. In order to find an accurate program anchor point, refer to the following Hadoop design documents. Reference Hadoop HDFS file system Append / Hflush / Read design documents ...

Today, the company opened the mailbox and was pleasantly surprised to find http://www.aliyun.com/zixun/aggregation/13461.html ">mongodb's News Letter, Open a look unexpectedly is 2.0 update, haha, so can't wait to start to try, because I usually only maintain the database, does not involve the development part, all the understanding is limited, most of the translation mainly. The following is the official document address: Http://www.mongodb.org/displ ...

Distributed Ho Deng of low cost cloud storage data for load balancing in IoT environment, Min, in order to meet the requirement of node mobility and real-time data access in IoT terminals, this paper proposes a storage server selection method combining data access point location and access frequency with low access cost according to the pattern of replica distribution and access in cloud storage.   Considering the impact of load on the access cost, the load balancing mechanism is proposed by dynamically updating the cost matrix. Keywords: cloud storage, Internet of things, replica distribution, load ...

kafka different versions. kafka-0.8.2 What's new? Producer no longer differentiates between sync and async, and all requests are sent asynchronously, improving client efficiency. The producer request will return a response object, including the offset or error message. This asynchronously bulk sends messages to the kafka broker node, which can reduce the overhead of server-side resources. The new producer and all server network communications are asynchronous, at ack = -...

"Editor's note" This blog author Luke Lovett is the MongoDB company's Java engineer, he demonstrated MONGO connector after 2 years of development after the metamorphosis-complete connector at both ends of the synchronization update. , Luke also shows how to implement fuzzy matching by Elasticsearch. The following is a translation: the introduction assumes that you are running MongoDB. Great, now that you have an exact match for all the queries that are based on the database. Now, imagine that you're building a text search work in your application ...