One, high availability principleSystem availability = Average trouble-free time/(mean time to repair + average no downtime)Improve system availability:Reduced mean time to repair (redundancy mechanism)Extended mean time-to-average trouble-freeMethods of improving system availability:HA cluster:Manually switchAutomatic switchingCluster switching:Failover: Failoverfailback: Fix TransferCluster resources:Vip:float IPIpvs rulesConstraint type:Position constraint (location)Permutation constraints (co
achieve memcached high availability (HA), assuming both machines are down. Just to show that your RP is too bad.Of course. You can also use three, four, or many other servers to improve ha.Test haTest background, Local LAN two server172.18.117.71 (memcacheport11211,magentport11210), 172.18.117.113 (memcacheport11211,magentport11210), and two serve R on the same LAN test machine, below is the test code:Import Com.danga.memcached.memcachedclient;import
#include int main (){int a,b,c,d,e,f,g,h,i,total=0;for (a = 1;a For (b= 1;b for (c = 1;c for (d = 1;d for (E = 1;e for (f = 1;f for (g = 1;g for (H =1;h for (i = 1;i}{if (a!=ba!=ca!=da!=ea!=fa!=ga!=ha!=ib!=cb!=db!=eb!=fb!=gb!=hb!=ic!=dc!=ec!=fc!=gc!=hc!=id!=ed!=fd!=gd!=hd!=ie!=fe!=ge!=he!=if!=gf!=hf!=ig!=hg!=ih!=ia*100+b*10+c+d*100+e*10+f = = g*100+h*10+i){total++;printf ("%d%d%d+%d%d%d =%d%d%d\n", a,b,c,d,e,f,g,h,i);}}printf ("total =%d", TOTAL/2);Ge
Tags: ha high availability cluster implementation based on NFS shared MySQL192.168.139.8 as Nfs-server, 192.168.139.2 and 192.168.13.4 are used to install MySQL___________________________________________________________________________________________ the following operations on 192.168.139.8[[email protected] ~]# fdisk-l//First to prepare a disk for the partition, to do the LV, then the LV format and then mount and//share with NFS, let the other node
Tags: mysqlDrbd+heartbeat + LVS + keepalived+ MySQLHardware: Master *: Install DRBD, Heartbeat,mysqlSlave*3: Installing MySQLKeep Alived Host * 2: Install LVS, keepalived (real server is slave)Application HostIP: Two master has an ha VIP1Two keepalived hosts have a LVS VIP2Write operation:Application Host (AS)->VIP1->DEV/DRBD (two master DRBD will synchronize in real time)MySQL copy operation:0) Start slave1) 3 Slave an I/O thread sends a request to V
+ real_server IP When real_server failure occurs, keepalived kills its own process, another keepalived get others shout VIP, take over, realize haTest:Find a LAN pc,ping mysql VIP (5.24), this time can be ping through theStop the MySQL service and see if the keepalived health check will trigger the script we wrote to see if the keepalived process existsSecond 5.22 installation keepalived and configuration# TAR-XVZF Keepalived-1.2.13.tar.gz# CD keepalived-1.2.13#./configure--prefix=/usr/local/ke
Tags: mysql master master slave semi-synchronous MySQL ha cluster: MYSQL-MHAIntroduction: Principle and mechanism of master-slave replicationto implement replication, you must first open The binary log(bin-log) function on the Master side , otherwise it cannot be implemented. Because the entire replication process is actually a variety of operations that are logged in the execution log that Slave obtains the log from the Master side and then executes
Label:See the official website configuration instructions are a bit different from the actual (CENTOS7), after some groping, the configuration process to record down 1. Download Mariadb-galera-server xinetd, the official website of the document is Mariadb-galera-server, after the search only Mariadb-galera-server, and after installing it, The previous mariadb will be replaced; A.mariadb.repo B.yum--enablerepo=mariadb.repo install-y mariadb-galera-server xinetd 2. Configuring Clustercheck and Gal
Tutorial on installing and using the extension module on PostgreSQL, postgresql extension module
Installation Module
Note: My runtime environments are Ubuntu 10.04 and PostgreSQL 8.4.
First, install the postgresql-contrib package and restart the database server. Then, check the contrib directory to see if there are som
In the previous chapters, we have understood the various replication concepts. This is not just a theoretical overview of the things that will enhance your consciousness for the next thing to be introduced, but will also introduce you to a broad topic.In this chapter, we will be closer to the actual solution and understand how PostgreSQL works internally and what replication means. We'll see what the so-called transaction log (XLOG) does, and how it w
PostgreSQL tutorial (1): Detailed description of data tables and detailed description of postgresql
I. Table definition:
For any relational database, tables are the core and basic object units of data storage. Now let's start from here.1. Create a table:Copy codeThe Code is as follows:Create table products (Product_no integer,Name text,Price numeric);2. delete a table:Copy codeThe Code is as follows:Drop ta
PostgreSQL tutorial (14): database maintenance, postgresql tutorial
I. Disk Space Restoration:
In PostgreSQL, the data rows deleted or updated using the delete and update statements are not actually deleted, the physical address of the old data row sets the row status to deleted or expired. Therefore, when data in a data table changes frequently, the space occupi
PostgreSQL replication cluster overview, PostgreSQL replication Cluster
For pg replication, high availability, and load balancing clusters, write an overview for future reference.
Pg has the following various replication-Based Cluster solutions, most of which were used, and some were not sorted out at the time. There are also many cluster configuration documents on the Internet. After this document, find a
Mac installs PostgreSQL by default, so that PostgreSQL can be accessed remotelyMac default PostgreSQL directory storage path is /usr/local/var/postgres/ in this directory, modify two files, one is postgresql.conf, one is pg_ Hba.conf, and finally a reboot.Modify Postresql.conflisten_addresses = ' * ' # Modify the configuration here to allow link
+ +)//each time from the first to start comparing, has been returned to the place no longer compare if(a[j]1]) { temp=a[j] ;//sort from big to small, with small numbers in the backa[j]=a[j+1]; A[j+1]=temp; } for(i=0; i) printf ("%d", A[i]);//Output Results return 0;}This method can compensate for the problem of the previous section and add a structure.1#include 2 structstudent{3 Charname[ +];4 intscore;5};//store student's name and score6 intMain () {7 structStuden
Cluster)A cluster is a loosely coupled multi-processor system composed of a group of independent computer systems. It communicates with each other through a network. Applications can transmit messages through the network shared memory to implement distributed computers.Load Balance)Server Load balancer is a dynamic balancing technology. It uses some tools to analyze data packets in real time, master the data traffic conditions in the network, and distribute tasks in a reasonable and balanced man
Configuration instructions:1. Use Openfiler to implement iscsi shared storage2. Implement the fence Function Through VMware ESXi5 virtual fence.3. Use RedHat 5.8 vmware-fence-soap to implement the RHCS fence device function.4. In this article, we created a RHCS experiment environment to test the RHCS Oracle HA function.I. Prepare the Basic Environment1. Prepare the Network EnvironmentNode1 and node2 nodes# Cat/etc/hosts192.168.14.100 node1192.168.14.1
EXtremeDB HA synchronization procedure, extremedb
Here is the description of synchronization procedure:1. Masterand replica databases have a ha_sequencer-64bit integer which is initializedby zero at startup.
2. Masterincrements the sequencer at each commit of a WRITE transaction and sends thesequencer value along with transaction data to the replica (s)
3. Ifthe replica successfully applies the specified ed transaction, it sets itssequencer to the sp
Two pcservers, one storage, win2003, oracle11g, and Rose ha
ORACLE_HOME is on the local hard disk, and oracle db is on the Storage
Spfile + Sid. ora is used on the local disk for storage as init + Sid. ora. The content in init + Sid. ora is spfile = 'Storage/spfile + Sid. ora'
By default, ORACLE_HOME under the local hard disk on both machines has a password file (PWD + Sid. ora ),This password file can be stored to adapt to the following situations:1.
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