disk access

RAID 0, also known as stripe (strip, string column) or striping, represents the highest storage performance in all RAID levels. RAID 0 improves storage performance by distributing continuous data to multiple disks for access. In this way, the system

The library is essentially a binary format of executable code that can be loaded into memory for execution. The database is divided into static and dynamic databases.Differences between static and dynamic Databases 1. Static function library The

We will not consider general VFS reading. This article uses the following functions as the root and analyzes them below:   do_generic_mapping_read(*ppos,*mapping,*desc)   The purpose of this function is to read data from the disk to the user

1. Storage Level: The access speed of the primary storage is much higher than the access speed of the disk. A classic data requires about 10 ms for disk access, while the memory only requires 60 ns !. There is another important reason why data

First, I would like to share my consistent point of view: From a performance perspective, MySQL will not lose to any other database system. If it has any shortcomings, it should mainly be in "functions" and "easy to manage. (The so-called

Raid was proposed by several people such as 1988. Since then, the disk array technology has developed rapidly and gradually matured. Raid and high performance (performance) are organized together by multiple disks as a logical volume to provide the

We have been engaged in the development of high-performance backend services for two years. The major support for this service is 100% CPU access in S. This data was obtained in the ultimate server test a few days ago. In fact, the speed of the

B-tree 1. B-tree Definition B-tree is a balanced multi-path search tree that is useful in file systems. Definition: an m-Level B-tree, an empty tree, or an m-tree that meets the following features:(1) Each node in the tree has at most m Subtrees;(2)

HDFS File System Optimization 1. System Perspective Storage Method. namenode adopts raid1 + 0, and datanode adopts the disk group jbod mode. In the scenario of sequential file reading, such as mapreduce, you can adjust the size of the file system

As we all know, the copy provided by Microsoft's operating system is "mentally retarded" with low speed and no resumable data transfer. In addition, copying will drag other applications down and occupy a large amount of File Cache. Therefore, many

Today we are free to talk to you about the usual daily limit! To view a daily limit, you need to consider the following four aspects: location, volume of the current day, whether to open the limit, and size of the daily limit. 1. the best and most

Document directory By Jason Eisner By Jason Eisner The biological anthropologist Loren Eiseley used to say there were two kinds of scientists: big-bone hunters and small-bone hunters. (He himself was a small-bone hunter, he said, fitting little

Return IDENTITY from INSERT I decided to start with a lot of problems: how to retrieve the IDENTITY value after executing SQL INSERT. Generally, the question is not how to write a query value, but where and when to search. In SQL Server, the

Download the sample source code or material in this article As a community-type software, high concurrency support and efficient and stable operation will always be the "final principle", and the effective and secure use of cache can achieve exactly

Summary: The presentation layer is an extremely important part of the application. This article discusses thin clients and smart clients, and provides guidance on how to select between them. Content on this page Introduction

This article explains how to use left join, cross join, and IDENTITY value retrieval to Improve the Performance of SQL Server-based applications or improve their scalability. What you will encounter: SQL queries in applications cannot respond in the

Improve query speed using SQL Indexes 1. Use indexes reasonablyAn index is an important data structure in a database. Its fundamental goal is to improve query efficiency. Currently, most database products adopt the isam index structure

In Linux, the free command is commonly used. Do you know the meaning of all rows output by free and the relationship between them? [Root @ localhost ~] # FreeTotal used free shared buffers cachedMem: 4038116 4010292 27824 0 205228 1343276-/+ Buffers/

I. B + tree 1. B + tree definition and features The B + tree is a variant of the B-tree and also a multi-path Search Tree: Its definition is basically the same as that of B-tree,: 1). The number of subtree pointers and keywords for non-leaf nodes is

Network Interface countersBytes Total/sec is the speed at which Bytes are sent and received on each network adapter, including frame characters. Network Interface \ Bytes encoded ED/sec is the sum of Network Interface \ Bytes encoded ED/sec and