Comments - Cannot increase open-files-limit

I created /lib/systemd/system/mysqld.service with the referenced settings - no change.

It's for sure really annoying, but, after attempting some additional steps as per the MariaDB docs, one can get it like below. The message is the one like below:

[Warning] InnoDB: innodb_open_files 65500 should not be greater than the open_files_limit 16364

I started the MariaDB Server 10.3.11 with the below configs:

mariadb@db-d01:$ my_print_defaults mysqld | grep files --innodb_open_files=65533 --open_files_limit=65533

I suspected something was blocking the limits of open_files_limit while innodb_open_files were going over and giving me that message. Looking for additional documents pointed by Ian Gilfillan, I found the below that the open_files_limit is limited by default at 16k (16364); a number which appears everywhere.

So, to increase that number, as we need to take it to `65533` to give it a full room, we need to change the `LimitNOFILE=16364` to `LimitNOFILE=65533` in the mariadb.service unit and enter the below command:

mariadb-dba@mortality-db-d01:$ sudo systemctl daemon-reload

It’s going to reload units located under the systemD subsystem which is going to make it possible to start the `mariadb.service` with that new definition. The ulimit is not an option anymore to tune open files, so, we check the new limit out of prlimit, as below:

mariadb@db-d01:$ sudo prlimit --pid=$(pidof mysqld) | grep NOFILE NOFILE max number of open files 65533 65533

Why prlimit? https://lzone.de/cheat-sheet/ulimit

And then, we can add to the current configuration file the below: --innodb_open_files=65533 --open_files_limit=65533

No warnings on the error log enymore: `2018-12-13 10:40:59 0 [Note] InnoDB: Using Linux native AIO 2018-12-13 10:40:59 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins 2018-12-13 10:40:59 0 [Note] InnoDB: Uses event mutexes 2018-12-13 10:40:59 0 [Note] InnoDB: Compressed tables use zlib 1.2.8 2018-12-13 10:40:59 0 [Note] InnoDB: Number of pools: 1 2018-12-13 10:40:59 0 [Note] InnoDB: Using SSE2 crc32 instructions 2018-12-13 10:40:59 0 [Note] InnoDB: Initializing buffer pool, total size = 7G, instances = 8, chunk size = 128M 2018-12-13 10:40:59 0 [Note] InnoDB: Completed initialization of buffer pool 2018-12-13 10:40:59 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority(). 2018-12-13 10:41:00 0 [Note] InnoDB: 128 out of 128 rollback segments are active. 2018-12-13 10:41:00 0 [Note] InnoDB: Creating shared tablespace for temporary tables 2018-12-13 10:41:00 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ... 2018-12-13 10:41:00 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB. 2018-12-13 10:41:00 0 [Note] InnoDB: 10.3.11 started; log sequence number 105534396886311; transaction id 929353557 2018-12-13 10:41:00 0 [Note] InnoDB: Loading buffer pool(s) from /Database/prod/ib_buffer_pool 2018-12-13 10:41:00 0 [Note] Plugin 'FEEDBACK' is disabled. 2018-12-13 10:41:00 0 [Note] Server socket created on IP: '0.0.0.0'. 2018-12-13 10:41:00 0 [Note] Server socket created on IP: '0.0.0.0'. 2018-12-13 10:41:00 0 [Warning] 'proxies_priv' entry '@% root@db07' ignored in --skip-name-resolve mode. 2018-12-13 10:41:00 0 [Note] Reading of all Master_info entries succeded 2018-12-13 10:41:00 0 [Note] Added new Master_info '' to hash table 2018-12-13 10:41:00 0 [Note] /usr/sbin/mysqld: ready for connections. Version: '10.3.11-MariaDB-1:10.3.11+mariaxenial-log' socket: '/var/run/mysqld/mysqld.sock' port: 3306 mariadb.org binary distribution 2018-12-13 10:41:52 0 [Note] InnoDB: Buffer pool(s) load completed at 181213 10:41:52

So, that way, you can raise the files limite.