I. Introduction
Storage Systems background
There are three types of storage systems:
the RDBMS
Oracle, DH2, PostgreSQL, MySQL, SQL Server
the NoSQL:
KV the NoSQL: Redis, the memcached
-column Column Family NoSQL: HBase, each line of each field can be retained n parts, a field is stored according to
a document Documentation NoSQL: MongoDB
schema NoSQL Graph: Neo4j
NewSQL
aerospike, foundationDB, rethinkDB ...
1. What is redis
redis is an open source use written in ANSI C, support network, based on the persistence of memory can log type, key-value database (a key-value storage systems), supports multiple languages API
It is an advanced key-value database, similar with memcached, but redis data can be persistent, and supports data types richer, while also supporting union, intersection, and complement computing services end of the set, and support a variety of sorting .
2, features:
And memcache used to compare, but redis is nosql, based on the stored key-value (key) data structure that can store keys, dictionaries, charts,
fully working in memory, data is stored in memory, a good performance, data cycle of backup to your hard disk (persistent) single-threaded server
can be extended by lua script
support sentinel master-slave architecture highly available
distributed
3, performance
Although the single-threaded, kv is a mere simple memory cpu generally not form a bottleneck, official test 50 times 10w concurrent requests, write rate is 110,000 times / s, the speed of reading is 81000 times / s, the size of the read and write is 256bytes string;
4, persistence persistence
RDB: snapshot, binary format; according to pre-customized policies, periodically save data to disk; the data files by default dump.rdb;
clients can also use an explicit command to start the snapshot SAVA or BGSAVE save mechanism;
the SAVE: synchronization, snapshots saved in the main thread; this time will block all client requests;
bgsave: asynchronous,
AOF of: Append Only file
records for each write operation to the end of the file specified for persistence; when redis restart, re-execute the file by the command to rebuild the database in memory;
BGREWRITEAOF: AOF overwriting files;
not read AOF file is in use, but by the data in memory in a manner commands saved to a temporary file, replacing the original files after the completion of AOF;
5 is a data structure server that supports value types are:
String string, List list, Hash hash, Set collection, Sorted Set ordered set, Bitmap, HyperLoglog
Strings:
SET key value [EX #] [NX|XX]
GET
INCR
DECR
EXIST
Lists:
LPUSH
RPUSH
LPOP
RPOP
LINDEX
LSET
Sets:
SADD
SINTER
SUNION
SPOP
SISMEMBER
Sorted Sets:
ZADD
ZRANGE
ZCARD
ZRANK
Hashem:
HSET
HSETNX
HGET
HKEY
whales
HDEL
Bitmaps, HyperLogLog
6, daemon
Listening port 6379 / tcp
7, database comparison
Common database feature comparison
| name | Database Type | Data Storage Options | Action Type | Remark |
| repeat | Memory storage, nosql database | Support for strings, lists, sets, hash mark, ordered collection | Add, delete, modify, update, | Support for distributed storage, master-slave synchronization and high availability, single-threaded |
| memcached | Memory Database Cache | Have a mapping between key | Add, delete, modify, update, | Support multithreading |
| mysql | A typical relational database, RDBMS | Database consists of more than tables, each table contains multiple rows | Add, delete, modify, update, | Support for ACID properties |
| postgresql | A typical relational database, RDBMS | Database consists of more than tables, each table contains multiple rows | Add, delete, modify, update, | Support for ACID properties |
| mongodb | Hard disk storage, nosql database | The database contains multiple tables | Add, delete, modify, update, | From the master copy, slice, replica set, spatial index |
Comparison between 8 and briefly memcached
redis kv only supports simple data types, support list, set, hash and other data structures
redis support data backup
redis support data persistence, data in memory can be kept on disk, restart time can be loaded using
Cluster, memcache do not support cluster, coexistence of multiple memcache
9, redis the master / slave replication:
Support more than one master slave
slave can introduce links to other slave master link to replace him
In the master copy is non-blocking, the slave is blocked
Copy utilized to provide scalability, only provides inquiry and data redundancy in the slave terminal
10, application scenarios
Cache (data queries, short connections, news content, goods, content, etc.)
Distributed cluster architecture separate session
Chat online buddy list
Task queue (spike, buy, 12306)
Application Ranking
Website statistics
Statistics
In order to address the high concurrency, high availability, high scalability, large data storage and other issues arising database solutions
Second, the master-slave replication mechanism
After redis redis solved the persistence service can restart to restore persistent data disk into memory, but redis server hard disk is broken will result in data loss, in order to avoid this single point of failure will have a master replication mechanism from
From a multi-master configuration
Will not be blocked from the master copy master, when synchronizing data, master can continue to process client requests
That may be a redis master may be from
Third, the multi-instance configuration redis
1, download and install the software source
http://download.redis.io/releases/redis-5.0.4.tar.gz
If the source installation Download Source
If you configure yum install source
rpm -ivh http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
2, is mounted in two installation
1), yum install
Direct yum install redis
systemctl enable redis
systemctl start redis
Dependencies Resolved #一些依赖 ==================================================================================================================== Package Arch Version Repository Size ==================================================================================================================== Installing: redis x86_64 3.2.12-2.el7 epel 544 k Installing for dependencies: jemalloc x86_64 3.6.0-1.el7 epel 105 k Transaction Summary ==================================================================================================================== Install 1 Package (+1 Dependent package)
Complete! [root@web1 ~]# systemctl start redis [root@web1 ~]# systemctl enable redis Created symlink from /etc/systemd/system/multi-user.target.wants/redis.service to /usr/lib/systemd/system/redis.service. [root@web1 ~]# netstat -untlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 2570/redis-server 1 tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/systemd tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 2050/nginx: master tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN 2176/dnsmasq tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 875/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 879/cupsd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2035/master tcp6 0 0 :::111 :::* LISTEN 1/systemd tcp6 0 0 :::80 :::* LISTEN 2050/nginx: master tcp6 0 0 :::22 :::* LISTEN 875/sshd tcp6 0 0 ::1:631 :::* LISTEN 879/cupsd tcp6 0 0 ::1:25 :::* LISTEN 2035/master udp 0 0 0.0.0.0:5353 0.0.0.0:* 574/avahi-daemon: r udp 0 0 127.0.0.1:323 0.0.0.0:* 2334/chronyd udp 0 0 0.0.0.0:52822 0.0.0.0:* 574/avahi-daemon: r udp 0 0 192.168.122.1:53 0.0.0.0:* 2176/dnsmasq udp 0 0 0.0.0.0:67 0.0.0.0:* 2176/dnsmasq udp 0 0 0.0.0.0:177 0.0.0.0:* 890/lightdm udp6 0 0 ::1:323 :::* 2334/chronyd udp6 0 0 :::177 :::* 890/lightdm [root@web1 ~]#
2), compile and install
Unzip -> compile -> copy -> Start
The compile and install a new version mkdir / the Data cd / the Data upload and download packages into this directory Redis - 5.0 . 4 . Tar .gz tar redis- 5.0 . 4 . Tar .gz cd rredis - 5.0 . 4 the make
3, compile and install and start
1) Create a folder and copy the key file
mkdir /data/redis2 cp redis.conf /data/redis2 cp src/redis-server /data/redis2 cd /data/redis2/
2) edit the configuration file
the redis.conf
Port 6380
appendOnly NO Yes // log switching, packet error log is not, binary recording data changes
PidFile / var / RUN / redis_6380.pid // PID name logfile " /data/redis2/redis.log " // log log yes daemonize // backstage start
dbfilename dump.rbd // persistent data file
3) Start
[root@web1 redis2]# ./redis-server ./redis.conf [root@web1 redis2]# netstat -tunlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 2570/redis-server 1 tcp 0 0 192.168.216.51:6380 0.0.0.0:* LISTEN 15434/./redis-serve tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/systemd tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 2050/nginx: master tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN 2176/dnsmasq tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 875/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 879/cupsd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 2035/master tcp6 0 0 :::111 :::* LISTEN 1/systemd tcp6 0 0 :::80 :::* LISTEN 2050/nginx: master tcp6 0 0 :::22 :::* LISTEN 875/sshd tcp6 0 0 ::1:631 :::* LISTEN 879/cupsd tcp6 0 0 ::1:25 :::* LISTEN 2035/master udp 0 0 0.0.0.0:5353 0.0.0.0:* 574/avahi-daemon: r udp 0 0 127.0.0.1:323 0.0.0.0:* 2334/chronyd udp 0 0 0.0.0.0:52822 0.0.0.0:* 574/avahi-daemon: r udp 0 0 192.168.122.1:53 0.0.0.0:* 2176/dnsmasq udp 0 0 0.0.0.0:67 0.0.0.0:* 2176/dnsmasq udp 0 0 0.0.0.0:177 0.0.0.0:* 890/lightdm udp6 0 0 ::1:323 :::* 2334/chronyd udp6 0 0 :::177 :::* 890/lightdm [root@web1 redis2]#
4) variable, assign a value, normally closed, non-normal shutdown
[root @ web1 redis2] # Redis-cli -h 192.168 . 216.51 -p 6380 192.168 . 216.51 : 6380 > 192.168 . 216.51 : 6380 > 192.168 . 216.51 : 6380 > 192.168 . 216.51 : 6380 > the SET Home ZXG // assign the OK 192.168 . 216.51 : 6380 > GET Home // value " ZXG " 192.168 . 216.51 : 6380 > GET abc123 (error) ERR wrong number of arguments for 'get' command 192.168.216.51:6380> set abc 123 OK 192.168.216.51:6380> get abc "123"192.168.216.51:6380> KEYS * //查看所有的key 1) "abc" 2) "home" 192.168.216.51:6380>
192.168.216.51:6380> SHUTDOWN // normally closed, non-normal shutdown is kill the
Fourth, the master-slave configuration
1, the configuration from the server
redis master-slave configuration is very simple, just need to change from one configuration server to
the redis.conf
slaveof 192.168.216.51 6379
2, start the service
[root@web2 ~]# systemctl start redis
[root@web2 ~]# systemctl enable redis
3, viewing the main test results from the state
[root@web1 redis2]# redis-cli -h 192.168.216.51 -p 6379 192.168.216.51:6379> info replication # Replication role:master connected_slaves:1 slave0:ip=192.168.216.52,port=6379,state=online,offset=99,lag=0 master_repl_offset:99 repl_backlog_active:1 repl_backlog_size:1048576 repl_backlog_first_byte_offset:2 repl_backlog_histlen:98 192.168.216.51:6379>
127.0.0.1:6379> info replication
# Replication
role:slave
master_host:192.168.216.51
master_port:6379
master_link_status:up
master_last_io_seconds_ago:3
master_sync_in_progress:0
slave_repl_offset:253
slave_priority:100
slave_read_only:1
connected_slaves:0
master_repl_offset:0
repl_backlog_active:0
repl_backlog_size:1048576
repl_backlog_first_byte_offset:0
repl_backlog_histlen:0
127.0.0.1:6379>
Note 1: Read-only from the server
New master key test zxg
192.168.216.51:6379> set test zxg OK 192.168.216.51:6379> get test "zxg" 192.168.216.51:6379>
slave see if there is value
127.0.0.1:6379> get test "zxg" 127.0.0.1:6379>
Please indicate the source: https://www.cnblogs.com/zhangxingeng/p/10743476.html