mirror of
https://github.com/fluencelabs/redis
synced 2025-03-19 00:50:50 +00:00
Currently replication offsets could be used into a limited way in order to understand, out of a set of slaves, what is the one with the most updated data. For example this comparison is possible of N slaves were replicating all with the same master. However the replication offset was not transferred from master to slaves (that are later promoted as masters) in any way, so for instance if there were three instances A, B, C, with A master and B and C replication from A, the following could happen: C disconnects from A. B is turned into master. A is switched to master of B. B receives some write. In this context there was no way to compare the offset of A and C, because B would use its own local master replication offset as replication offset to initialize the replication with A. With this commit what happens is that when B is turned into master it inherits the replication offset from A, making A and C comparable. In the above case assuming no inconsistencies are created during the disconnection and failover process, A will show to have a replication offset greater than C. Note that this does not mean offsets are always comparable to understand what is, in a set of instances, since in more complex examples the replica with the higher replication offset could be partitioned away when picking the instance to elect as new master. However this in general improves the ability of a system to try to pick a good replica to promote to master.
Where to find complete Redis documentation? ------------------------------------------- This README is just a fast "quick start" document. You can find more detailed documentation at http://redis.io Building Redis -------------- Redis can be compiled and used on Linux, OSX, OpenBSD, NetBSD, FreeBSD. We support big endian and little endian architectures. It may compile on Solaris derived systems (for instance SmartOS) but our support for this platform is "best effort" and Redis is not guaranteed to work as well as in Linux, OSX, and *BSD there. It is as simple as: % make You can run a 32 bit Redis binary using: % make 32bit After building Redis is a good idea to test it, using: % make test Fixing problems building 32 bit binaries --------- If after building Redis with a 32 bit target you need to rebuild it with a 64 bit target, or the other way around, you need to perform a "make distclean" in the root directory of the Redis distribution. In case of build errors when trying to build a 32 bit binary of Redis, try the following steps: * Install the packages libc6-dev-i386 (also try g++-multilib). * Try using the following command line instead of "make 32bit": make CFLAGS="-m32 -march=native" LDFLAGS="-m32" Allocator --------- Selecting a non-default memory allocator when building Redis is done by setting the `MALLOC` environment variable. Redis is compiled and linked against libc malloc by default, with the exception of jemalloc being the default on Linux systems. This default was picked because jemalloc has proven to have fewer fragmentation problems than libc malloc. To force compiling against libc malloc, use: % make MALLOC=libc To compile against jemalloc on Mac OS X systems, use: % make MALLOC=jemalloc Verbose build ------------- Redis will build with a user friendly colorized output by default. If you want to see a more verbose output use the following: % make V=1 Running Redis ------------- To run Redis with the default configuration just type: % cd src % ./redis-server If you want to provide your redis.conf, you have to run it using an additional parameter (the path of the configuration file): % cd src % ./redis-server /path/to/redis.conf It is possible to alter the Redis configuration passing parameters directly as options using the command line. Examples: % ./redis-server --port 9999 --slaveof 127.0.0.1 6379 % ./redis-server /etc/redis/6379.conf --loglevel debug All the options in redis.conf are also supported as options using the command line, with exactly the same name. Playing with Redis ------------------ You can use redis-cli to play with Redis. Start a redis-server instance, then in another terminal try the following: % cd src % ./redis-cli redis> ping PONG redis> set foo bar OK redis> get foo "bar" redis> incr mycounter (integer) 1 redis> incr mycounter (integer) 2 redis> You can find the list of all the available commands here: http://redis.io/commands Installing Redis ----------------- In order to install Redis binaries into /usr/local/bin just use: % make install You can use "make PREFIX=/some/other/directory install" if you wish to use a different destination. Make install will just install binaries in your system, but will not configure init scripts and configuration files in the appropriate place. This is not needed if you want just to play a bit with Redis, but if you are installing it the proper way for a production system, we have a script doing this for Ubuntu and Debian systems: % cd utils % ./install_server The script will ask you a few questions and will setup everything you need to run Redis properly as a background daemon that will start again on system reboots. You'll be able to stop and start Redis using the script named /etc/init.d/redis_<portnumber>, for instance /etc/init.d/redis_6379. Code contributions --- Note: by contributing code to the Redis project in any form, including sending a pull request via Github, a code fragment or patch via private email or public discussion groups, you agree to release your code under the terms of the BSD license that you can find in the COPYING file included in the Redis source distribution. Please see the CONTRIBUTING file in this source distribution for more information. Enjoy!
Description
Languages
C
85.6%
Tcl
13.2%
Ruby
0.4%
Shell
0.4%
Makefile
0.3%
Other
0.1%