MariaDB 10.3.27 Memory usage problem Greetings!
I tried to optimize MariaDB configuration with my.cnf. Everything was OK, but available memory falling down each hour. I'm using MariaDB with Zabbix server on the same server. CPU: 4 Cores, RAM: 8 GB (before was 4 GB and it was OK), HDD: 128 GB.
Could you please tell me what should I fix?
[mysqld]
user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /var/lib/mysql
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql

connect_timeout                 = 60
wait_timeout                    = 28800
max_connections                 = 200
max_allowed_packet              = 64M
max_connect_errors              = 1000


tmp_table_size                  = 256M
max_heap_table_size             = 256M
table_open_cache                = 1024

log_error                       = /var/log/mysql/mysql-error.log
slow_query_log_file             = /var/log/mysql/mysql-slow.log
slow_query_log                  = 1
long_query_time                 = 5

innodb_file_per_table           = 1
innodb_status_file              = 1
innodb_buffer_pool_size         = 5G
innodb_flush_method             = O_DIRECT
innodb_io_capacity              = 2000
innodb_log_file_size            = 640M
innodb_log_buffer_size          = 16M
innodb_buffer_pool_instances    = 5

skip-external-locking
bind-address                    = 127.0.0.1
event_scheduler                 = 1
query_cache_type                = 0
join_buffer_size                = 256K
read_buffer_size                = 256K
read_rnd_buffer_size            = 256K
sort_buffer_size                = 256K
key_buffer_size                 = 16M
thread_stack                    = 192K
thread_cache_size               = 8
myisam-recover-options          = BACKUP
query_cache_limit               = 2M
query_cache_size                = 128M
expire_logs_days                = 10
max_binlog_size                 = 100M
These are dangerously big; lower them to about 1% of RAM.
tmp_table_size                  = 256M
max_heap_table_size             = 256M

Some of the allocated space gradually grows until it hits a limit derived from a setting or combination of settings.
Do you have anything other than MySQL running on that machine?  If not, I don't expect it to fill up the 8GB.