MongDB 启动警告 WARNING: soft rlimits too low

# mongo
MongoDB shell version: 3.0.2
connecting to: test
Server has startup warnings: 
2015-05-09T12:34:19.688-0700 I CONTROL  [initandlisten] 
2015-05-09T12:34:19.688-0700 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 1024 processes, 64000 files. Number of processes should be at least 32000 : 0.5 times number of files.
> 

mongodb当前限制：1024 processes, 64000 files

mongodb建议要求：processes = 0.5*files=32000（至少）

所以需要将 processes  从1024 改为 32000 或更大.

查看当前mongodb进程信息：

[root@localhost ~]# ps -ef | grep mongod

mongod   24283     1  0 12:35 ?        00:00:04 /usr/bin/mongod -f /etc/mongod.confroot     24240 22049  0 12:45 pts/2    00:00:00 grep mongod

[root@localhost ~]# cat /proc/24283/limits

#可以看到限制：Max processes，Max open files 

Limit                     Soft Limit           Hard Limit           Units     Max cpu time              unlimited            unlimited            seconds   Max file size             unlimited            unlimited            bytes     Max data size             unlimited            unlimited            bytes     Max stack size            10485760             unlimited            bytes     Max core file size        0                    unlimited            bytes     Max resident set          unlimited            unlimited            bytes     Max processes             1024                 32000                processes Max open files            64000                64000                files     Max locked memory         65536                65536                bytes     Max address space         unlimited            unlimited            bytes     Max file locks            unlimited            unlimited            locks     Max pending signals       14833                14833                signals   Max msgqueue size         819200               819200               bytes     Max nice priority         0                    0                    Max realtime priority     0                    0                    Max realtime timeout      unlimited            unlimited            us    

修改 Max processes 或者 files ，有几种方法：

方法一：

修改配置文件 /etc/security/limits.d/90-nproc.conf  

[root@localhost ~]# vi /etc/security/limits.d/90-nproc.conf 

*          soft    nproc     1024改为:*          soft    nproc     32000

重启 mongod 服务：

[root@localhost ~]# service mongod restart

方法二：

修改配置文件 /etc/security/limits.conf，添加配置信息：

[root@localhost ~]# vi /etc/security/limits.conf

mongod soft nofile 64000mongod hard nofile 64000mongod soft nproc 32000mongod hard nproc 32000

重启 mongod 服务：

[root@localhost ~]# service mongod restart

也可以查看 limits.conf 更多配置信息和使用方法：

[root@localhost ~]# man limits.conf

查看系统限制：

[root@localhost ~]# ulimit -a

core file size          (blocks, -c) 0data seg size           (kbytes, -d) unlimitedscheduling priority             (-e) 0file size               (blocks, -f) unlimitedpending signals                 (-i) 14833max locked memory       (kbytes, -l) 64max memory size         (kbytes, -m) unlimitedopen files                      (-n) 1024pipe size            (512 bytes, -p) 8POSIX message queues     (bytes, -q) 819200real-time priority              (-r) 0stack size              (kbytes, -s) 10240cpu time               (seconds, -t) unlimitedmax user processes              (-u) 14833virtual memory          (kbytes, -v) unlimitedfile locks                      (-x) unlimited

mongodb推荐设置：

-f (file size): unlimited-t (cpu time): unlimited-v (virtual memory): unlimited-n (open files): 64000-m (memory size): unlimited-u (processes/threads): 64000

直接在当前shell中设置：ulimit -n <value>

ulimit -f unlimitedulimit -t unlimitedulimit -v unlimitedulimit -n 64000ulimit -m unlimitedulimit -u 64000

若要系统启动时在所有生效，将上面的 ulimit 添加到 /etc/profile 

[root@localhost ~]# vi /etc/profile

参考： UNIX ulimit Settings