Centos7 Server optimization ( now its high CPU and Memory Uses more then 300%)

Hi All, I have Centos7 server, magento 1.9 website on it, with 6 core CPU and 12 GB memory, active user all the time 20-30. from last few days my server resources are very high, CPU and Memory both are above 100% in use. i run "./[login to view URL]" Recommendations : -------- Recommendations --------------------------------------------------------------------------- General recommendations: Control warning line(s) into /var/log/mariadb/[login to view URL] file Control error line(s) into /var/log/mariadb/[login to view URL] file MySQL started within last 24 hours - recommendations may be inaccurate Enable the slow query log to troubleshoot bad queries Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1 Increasing the query_cache size over 128M may reduce performance Adjust your join queries to always utilize indexes Increase table_open_cache gradually to avoid file descriptor limits Read this before increasing table_open_cache over 64: [login to view URL] Beware that open_files_limit (1024) variable should be greater than table_open_cache (400) Performance shouldn't be activated for MySQL and MariaDB 5.5 and lower version Consider installing Sys schema from [login to view URL] Variables to adjust: query_cache_type (=0) query_cache_size (> 128M) [see warning above] join_buffer_size (> 128.0K, or always use indexes with joins) table_open_cache (> 400) performance_schema = OFF disable PFS innodb_file_per_table=ON innodb_buffer_pool_size (>= 5G) if possible. innodb_log_file_size * innodb_log_files_in_group should be equals to 1/4 of buffer pool size (=1G) if possible. innodb_buffer_pool_instances(=3) innodb_log_buffer_size (>= 8M)