table_open_cache increase issue - MariaDB 10.2

Question

I'm trying to increase to 9000 but MariaDB sets it at 4895 automatically.

Here is my simple config https://pastebin.com/raw/4eFiuFSv

MySQLTuner output:

Control warning line(s) into /var/lib/mysql/cp.goal.ge.err file
Control error line(s) into /var/lib/mysql/cp.goal.ge.err file
Restrict Host for user@% to user@SpecificDNSorIp
Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
Temporary table size is already large - reduce result set size
Reduce your SELECT DISTINCT queries without LIMIT clauses
Increase table_open_cache gradually to avoid file descriptor limits
Read this before increasing table_open_cache over 64:

Beware that open_files_limit (10000) variable

should be greater than table_open_cache (4895)

Optimize queries and/or use InnoDB to reduce lock wait
Consider installing Sys schema from https://github.com/mysql/mysql-sys

Variables to adjust:
    query_cache_size (=0)
    query_cache_type (=0)
    query_cache_size (> 125M)
    table_open_cache (> 4895)

Answer 1

I can see 3 different reasons why MariaDB might reset this variable. In order of most to least likely explanation:

1. You have another .cnf file where the table_open_cache variable is being set to 4895.
2. The MariaDB Systemd unit file (or SysV init script on older Linux versions) is overwriting the variable value you've set.
3. You're running a non-standard MariaDB server that's been compiled with a hard-coded value for table_open_cache. (Unlikely!)

Additionally, it's possible that another software (such as cPanel) might change the variable dynamically after MariaDB has started.

To see which options the MariaDB server will get from the option files, run:

mysqld --print-defaults 

To find all the places where the MariaDB server is looking for .cnf files, run:

mysqld --verbose --help | grep -A 1 'Default options are read'

You can then grep each of these files to see if you find any instances of table_open_cache or table-open-cache.

For reference, you should be able to see the current value of the variable with:

show global variables like 'table_open_cache';

And you may also want to consult this page in the MariaDB Knowledge Base: Optimizing table_open_cache.