语篇服务器无法从与redis相关的错误开始。

Question

Rails服务器在开发或生产过程中都无法在语篇项目中启动。下面是试图以dev模式启动服务器时的日志。应用程序已经安装并一直在工作，它以生产模式部署在AWS上，并重新启动独角兽加载应用程序一次又一次，url停止使用错误消息进行响应。

开发日志来自$rails的

rb t@ip-XXX-XX-XX-XX-app:/var/www/discourse# vi 
config/environments/development.r
root@ip-172-31-25-46-app:/var/www/discourse# rails s
=> Booting Puma
=> Rails 5.1.4 application starting in production 
=> Run `rails server -h` for more startup options
Exiting
bundler: failed to load command: script/rails (script/rails)
Redis::CommandError: ERR Error running script (call to f_b06356ba4628144e123b652c99605b873107c9be): @user_script:14: @user_script: 14: -MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error.   
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-3.3.5/lib/redis/client.rb:121:in `call'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-3.3.5/lib/redis.rb:2399:in `block in _eval'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-3.3.5/lib/redis.rb:58:in `block in synchronize'
/usr/local/lib/ruby/2.4.0/monitor.rb:214:in `mon_synchronize'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-3.3.5/lib/redis.rb:58:in `synchronize'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-3.3.5/lib/redis.rb:2398:in `_eval'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-3.3.5/lib/redis.rb:2450:in `evalsha'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/message_bus-2.1.1/lib/message_bus/backends/redis.rb:380:in `cached_eval'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/message_bus-2.1.1/lib/message_bus/backends/redis.rb:140:in `publish'
/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/message_bus-2.1.1/lib/message_bus.rb:248:in `publish'
/var/www/discourse/lib/distributed_cache.rb:72:in `publish'

**生产日志**

/var/www/discourse/lib/demon/base.rb:109:in `ensure_running'
            /var/www/discourse/lib/demon/base.rb:34:in `block in ensure_running'
            /var/www/discourse/lib/demon/base.rb:33:in `each'
            /var/www/discourse/lib/demon/base.rb:33:in `ensure_running'
            config/unicorn.conf.rb:145:in `master_sleep'
            /var/www/discourse/vendor/bundle/ruby/2.3.0/gems/unicorn-5.1.0/lib/unicorn/http_server.rb:284:in `join'
            /var/www/discourse/vendor/bundle/ruby/2.3.0/gems/unicorn-5.1.0/bin/unicorn:126:in `<top (required)>'
            /var/www/discourse/vendor/bundle/ruby/2.3.0/bin/unicorn:23:in `load'
            /var/www/discourse/vendor/bundle/ruby/2.3.0/bin/unicorn:23:in `<main>'
            E, [2018-01-04T08:43:37.949928 #60] ERROR -- : reaped #<Process::Status: pid 5870 exit 1> worker=unknown
            Detected dead worker 5870, restarting...
            Loading Sidekiq in process id 5883
            Failed to report error: MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error. 4 Redis::CommandError (MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error.)
            /var/www/discourse/vendor/bundle/ruby/2.3.0/gems/redis-3.3.0/lib/redis/client.rb:121:in `call' web-exception

Redis日志

   47:M 17 Jan 09:38:01.070 # Can't save in background: fork: Cannot allocate memory
   47:M 17 Jan 09:38:07.087 * 10000 changes in 60 seconds. Saving...

Answer 1

问题已经解决，编辑了此文件

/etc/sysctl.conf，最后添加行

   vm.overcommit_memory=1 

在此之后重新启动sysctl。

  $ sudo sysctl -p /etc/sysctl.conf

Redis不需要操作系统认为的内存量，状态1意味着总是超额提交，永远不要检查。更多细节可以从Redis Docs中找到。