opex technologies

listIscsiadm--mode Discovery--type sendtargets--portal 192.168.4.103--discover #客户端探测服务器共享 (fill the server-side IP)Iscsiadm--mode node--targetname iqn.2016-03.com.haha.xixi:lele--portal 192.168.4.103:3260--login #登入共享存储/ETC/INIT.D/TGTD lsblk #发现共享存储/DEV/SDB1 can be formatted and used for partition mount (note:Note: It is absolutely impossible to mount the shared store on both hosts, or it will cause a file system crash!!! )iSCSI Service Application instance (MySQL)First, configure the applicat

characters is actually converted.C++primer 4th gives the standard practice of using the dynamic_cast operator.// pointer condition, if (Derived *derivedptr = dynamic_cast(baseptr) { // conversion succeeded } else{ // failure handling }Citation:// Citation Situation Try { const Derived d = dynamic_castconst derived>(b); // Success Situation } catch(bad_cast) { // failure handling }The logic of this piece of code is very strict:The scope of the Derive

events that are triggered at different stages of the build life cycle.1.open: Triggered when a connection is successfully established.2.error: Triggered when an error occurs, the connection cannot be sustained.3.close: Triggered when the connection is closed.The WebSocket object does not support DOM Level 2 event listeners, so each event handler must be defined using DOM level 0 syntax.var socket = new WebSocket(‘ws://www.example.com/server.php‘)socket.onopen = function () { alert(‘Connection

(Runnable r) {return new Thread ("athread-" + threadnumber.incrementandget ());}}Richer applications should be explored on their own, combined with their own needs to use the thread pool to achieve, the following analysis of Java thread pool implementation of a few more important content.Threadpoolexecutor and ScheduledthreadpoolexecutorThreadpoolexecutor and Scheduledthreadpoolexecutor are the core classes of Java implementation thread pools, and different types of thread pools are actually us

All of the previous frameworks have one thing in common: all open source is free, and those frameworks don't belong to Java EE specifications. These framework technologies are more comfortable in the face of small and medium-sized applications, but are stretched in front of large applications. 1. JSF Framework JSF is the abbreviation for Java Server faces, and like tapestry, JSF is also a framework for MVC development based on component technology, a

Java was originally staged in browsers and client machines. At the time, many people questioned whether it was suitable for server-side development. Now, with the increase in Third-party support for the JAVA2 platform Enterprise version, Java is widely accepted as one of the preferred platforms for developing enterprise server-side solutions. In this article I will explain 13 core technologies that support Java EE: JDBC, JNDI, EJBs, RMI, JSP, Java se

Article Description: front-end design horizontal development: Learn the technology related to the front-end. Today's conference, referred to the "horizontal development" of the word, refers to recommend you learn to deal with the front-end related technologies, such as: PHP In fact, the word "front end" was gradually rising in China in the 2005.Before that, the domestic website, usually table+asp to get everything done. The person who doe

-virtualized technology is shown in Figure 2. Figure 2: Semi-/quasi-virtualization technology With the gradual evolution of hardware virtualization technology, the performance of full virtualization running on Intel platforms has surpassed that of quasi-virtualized products, which is more pronounced on 64-bit operating systems. In addition, full virtualization does not require the inherent advantage of making any modifications to the client operating system. It can be predicted that hardware-ba

is to study the protection technology of "bridge". Currently there are several technologies for data exchange: Bridge Repair Strategy: The business agreement is passed directly, the data is not reorganized, the impact on speed is small, the security is weak N Firewall FW: Filtering the network layer N Multiple security gateways: Filtering from the network layer to the application layer, multiple checkpoint strategy Ferry strategy: The business a

staff to the wireless equipment irresponsible misuse also can cause the security hidden danger, for example, irresponsible assumptions open AP, open Wireless network card ad hoc mode, or mistaken for other people fake legitimate access point leads to information disclosure and so on "wireless network industry next competition in security, to open up wireless network applications in the new era, You must weave a higher-secure wireless network. "The safety of wireless networks will trigger the ne

principle difference is not small, is to solve the potential problems of the former solution, is as a former copy of the promotion or enhancement, open source has no perfect solution, but there is a continuous improvement of the solution, this is not one of the charm of open source?There may be differences in the technical details of different replications, but the essential things are the same.Of course, each copy has its own details, which can only be practiced in practical applications.This

Scenarios:Requires high service availability.Requires automatic failover.Ensure the integrity of the data.Advantages:Synchronous and asynchronous mirroring can be implemented according to the business.Fast failover recovery. Low hardware costs.Requirements:The principal server.mirror server.The witness server.Four. Failover clusteringApplication Scenarios:Hardware fail-over.Service failover.Manual failure or various other reasons.Advantages:Flexible cluster topologies based on the businessFast

: Count distinct (cardinality estimation) has been one of the SQL performance killers, if you can accept a certain error, you can use approximate algorithm. The approximate algorithm (NDV) has been implemented in Impala, and Presto is requested to blinkdb cooperation. Both are used Hyperloglog counting. Of course, not only count distinct can use approximate algorithms, but others, such as median, can also be used. ConclusionAlthough the relevant systems are now many, but also after several

Tags: ext UNC application Privacy start AC exp NoEveryone inevitably have their own privacy, some people like win system encryption technology, want to apply TA to Mac but, looked for a long time did not find, is not very irritating, today to everyone to popularize the encryption technology on the Mac.In fact, on Mac computers, if you have confidential files or folders that you do not want to be viewed by unauthorized users, you can encrypt files or folders by placing them in an encrypted disk i

With the development of IT software and hardware technology and business development, more and more communication networks are introduced and become standards in addition to the traditional PSTN network and 2G network, such as 3G network, LTE network, IMS network, WiMAX network, and Softswitch Network. This leads to a large increase in user data. With the surge in user data in the network, the original methods of storing and managing user data in their respective networks are increasingly unable

In the IT field where new technologies and new programming languages are emerging, some people say: "If you do not stay the same, it will be regressing." If you cannot master more than two mainstream programming languages or technologies, it is time to get rid of the society. Some people also think that "one trick is to eat all over the day", as long as you are proficient in a language technology, you can a

[Report of csdn on September] new technologies and technologiesProgramming LanguageSome people say that if they do not move, they will go backwards. If they are unable to master more than two mainstream programming languages or technologies, it will be a matter of time before they are eliminated. Some people also think that "one trick is to eat all over the day", as long as you are proficient in a language

Java was first launched on browsers and client machines. At that time, many people questioned whether it was suitable for server-side development. Now, with the increase in third-party support for the Java2 Platform Enterprise Edition (J2EE), Java is widely accepted as one of the preferred platforms for developing enterprise-level server solutions. The J2EE platform consists of a complete set of services, application interfaces (APIS), and Protocols. It provides Function Support for developing w

[Report of csdn on April 9] Technology New Programming Language Some people say that if they do not move, they will go backwards. If they are unable to master more than two mainstream programming languages or technologies, it will be a matter of time before they are eliminated. Some people think that"As long as you are proficient in a language technology, you can also become an IT professional. In the same way, in the face of endless

processing speed, data availability, data security, and dataset scalability. Connecting multiple databases together to form a database cluster is a natural idea. The Cluster technology uses a specific connection method to combine relatively low-price hardware devices and provides high-performance task processing capabilities. This article attempts to analyze and comment on the specific technologies and mainstream products used by the current major da