wavelink avalanche

Storage C1, C2 data. Because these virtual nodes are large in number and evenly distributed, they do not cause "avalanche" phenomena. PHP implementation of consistent hashing algorithm An interface is given below /** * Consistent Hash Implementation interface * Interface Consistenthash */interface consistenthash{//convert string to hash value public function chash ($STR);//Add a service To the server list, public function addserver ($server); Remove

devices ). The constant opening and closing of files slows down the SQL response time and consumes the CPU cycle. To check whether DB2 is closing the file, run the following command: 1 db2 "get snapshot for database on DBNAME" and find the following rows: 1 Database files closed = 0 if the value of the preceding parameter is not 0, the value of MAXFILOP is increased until the file is continuously opened and closed. 1 db2 "update db cfg for DBNAME using maxfilop n" 7. Lock The default value

Data encryption features: confidentiality, integrity, and identity authentication.Common cryptographic algorithmsSymmetric encryptionThe symmetric encryption algorithm uses the same key during encryption and decryption, and cannot have a valid management key.Symmetric encryption algorithms are: des;3des;aes:advanced;aes192 AES256 aes512;openssl;gpgOne-way encryptioncan effectively guarantee the integrity of the data, one-way encryption algorithm, extract the signature; as input, the output must

, the implementation is slightly complex, the same also faces the first way of the problem. However, there can be a dedicated Key manager that generates public and secret key pairs, delivers the public key to the client, and delivers the secret key to the server side, greatly reducing the likelihood of leaks. At the same time, even if the user guesses the public key of the client, it cannot decrypt the data submitted by other users, but can only forge the request.Measure-level protectionThe inte

As the world's largest Redis user, Sina has a lot of experience in development and operations. The author of this article from Sina, hope to provide some personal experience for the industry, so that everyone less detours.Purpose of UseFrom the first half of 2010 onwards, we began to try to use Redis, mainly for the following considerations. Performance is better than MySQL. The demand for performance is growing as business grows. A rich data type. Speed is the market in the Interne

of usability of the CQRS architecture.Traditional architecture, because the read and write is not separated, so the availability of reading and writing together to consider, the difficulty is more difficult. Because of the traditional architecture, if a system at the peak of concurrent write large, such as 2W, concurrent reading is also very large, such as 10W. The system must be optimized to support this high-concurrency write and query at the same time, or the system will be hung up at peak t

password, encrypted with the other's public key, and sent to each other. Data encryption. Features of Asymmetric encryption: Large key lengths, e.g. 512bits, 2048bits, 4096bits Encryption and decryption are used in relation to the keys in the key pair, respectively. Commonly used for digital signatures and key exchange One-way encryption: The characteristic code of the data is presented through a one-way hash function. Its usefulness is to ensure the integrity of

can be faulty or delayed, and if an application cannot fault-tolerant and isolate the failures it relies on, the application itself is at risk of being dragged down. In a high-traffic web site, once a single backend is delayed, it can cause all application resources (threads, queues, and so on) to be exhausted in a few seconds, resulting in the so-called avalanche effect (cascading Failure), which can paralyze the entire site in severe time. Service

Core knowledge of the site architectureNowadays, Internet products already occupy the majority of the software industry's wall to Jiangshan. As a test engineer, you are often dealing with the testing of Internet products, especially Web application products.At this point, if you want to do the Internet product functional testing other than testing, such as performance testing, stability testing, full-link pressure measurement, failover (Failover) testing, dynamic cluster capacity scaling testing

resolution: Name translationComputer-designated binary numbersBased on the name resolution library:/etc/groupGroup Category 2: Additional groups for users ' basic group usersGroup Category 3: Private group, with user name, and contains only one user; public group, group contains multiple users;Certification information:Whether the information provided by the login is consistent with the prior storage of the data;Password:/etc/shadow/etc/gshadowPassword Usage Policy:1, use random password;2. Min

Administrators, change groups password and member 4, List of users with the current group as additional groups: (comma delimiter) Specifies to view the passwd,shadow,group of a user, Gshadow methodgetent [Passwd,shadow,group, Gshadow] User nameFor example[Email protected] ~]# getent passwd qzxqzx:x:500:500:qzx:/home/qzx:/bin/bash[[email protected] ~]# getent group QZXQZX: X:500:[[email protected] ~]# getent Gshadow rootroot:::Compilation and inspection of passwd and group

not limited to:1) Top 10 of the world's most well-known engines, including engines produced by major gaming companies The Dead engine, the American EA Company re-made engines Avalanche Engine, Mt framework engine, Ghost cry game Do you know? That's what this is about. Anvil engine, Ubsoft's engine Ego engine Cold Frost Engine CryEngine IW engine Naughty Dog engine Unreal Engine 2) There is also a bun

alternative to Spiren T Avalanche and IXIA IxLoad.The tool is useful-performance loading of various application services, for testing Web and FTP servers and traffic GE Neration. Activities of each virtual client is logged and collected statistics includes information about resolving, connection EST Ablishment, sending of requests, receiving responses, headers and data received/sent, errors from Network, TLS/SSL and app Lication (HTTP, FTP) level eve

BC, BC on a node for the deletion and modification of data how to restore to a node? I saw the NRW model, but I didn't fully understand it. Answer 1 In the group, it is suggested that the server can use haproxy+keepalived to implement each machine master mode, in fact, the equivalent of a consistent hash of the ring really only 4 available target, but requires 8 servers to complete According to the landlord want to use consistent hashing algorithm, basically is to use Redis as a cache, rather

access paradigms (for example, displaying data in different forms on different pages), it may be difficult to make the cache expire or update, at the same time,/or you may need to tolerate expired data. A feasible alternative solution is to design a more fine-grained Cache mechanism. of course, it also has the disadvantage that multiple accesses to the cache will increase latency. 2. caching an object with high cost may lead to potential performance differences for users who do not hit the cach

two-tube structure, it can be read/written by the Unit. Technically,Flash is achieved by combining EPROM and EEPROM technology., A lot of Flash useProgramming by avalanche hot Electronic Injection, Used to erase and use Fowler-nordheim tuneling like EEPROM. But the main difference is that,Flash can erase large or whole blocks of the chip, which reduces the complexity of the design., It can not be the redundant tansister In the eeprom unit, so it

memcache and redis). The above PPT also focuses on this aspect. (2) cache avalanche When the cache system is restarted or all the caches expire at the same time (for example, some systems will uniformly fl most of the data into the cache at system startup to speed up, at this time, if the cache time is set to 24 hours, then after 24 hours, it will be a tragedy.) When the application system fails because it cannot withstand the pressure. (3) cac

Encryption and decryption 1. symmetric encryption2. asymmetric encryption3. Individual Encryption The encryption algorithms follow the following rules: kerckhoffs Principle Symmetric encryption: the same key is used for encryption and decryption.Commonly used 3DES, AES advanced encryption 128-bit, 192, and 256 Asymmetric encryption (public key encryption): encryption and decryptionIt is mainly used for authentication.Public Key secret algorithm: Paired appearanceRSA encryption can also be auth

function to calculate a particular piece of data, you will get a string of signatures, and is irreversible, this pattern is similar to "fingerprint" information, as long as the use of the same hash algorithm, no matter how many times the same data generated by the signature code is always the same, If the original data has changed, even if it is subtle, then the signature will also have a huge change, this phenomenon is called the avalanche effect. T

algorithms: DES, 3DES, AES Features: (1) encryption, decryption using the same key, (2) The original data is divided into fixed-size blocks, encrypted one by one. Defects: (1) Too many keys, (2) Key segmentation difficulties Public Key Cryptography : Keys are divided into public and private keys Public key: Extracted from the private key; available to all; PubKey Private key: Created by the tool and retained by the user, it must be guaranteed to be private; secret key Features: Data encrypted w