Server System variables are global values which can effect the behavior of various components. Server System variables are different to the variables used for storage engine configuration as they either do not affect or apply across multiple storage engines (where applicable).
The following Server System variables can impact storage configuration :
|
Parameter Name |
Description |
Default Value |
Recommended Value |
|---|---|---|---|
|
The path to the MySQL installation base directory. |
Microsoft Windows - C:\ProgramData\MySQL\MySQL Server<version>\ Linux - /var/lib/ |
Only change this if using a separate layout for data, binary and transaction log directories. |
|
|
The path to the MySQL server data directory. |
Microsoft Windows - C:\ProgramData\MySQL\MySQL Server<version>\Data Linux - /var/lib/mysql |
Only change this if using a separate layout for data, binary and transaction log directories. |
|
|
The number of open tables for all threads. |
2000 |
If the value of opened tables is too large (see Opened_tables status variable) then increase this value. |
|
|
The number of open tables cache instances. |
16 |
To improve scalability by reducing contention among sessions the open tables cache can be partitioned into several smaller cache instances. Modify this value in conjunction with table_open_cache to tune the workload to achieve higher performance. |
|
|
The number of file descriptors available to MySQL from the operating system |
5000 |
Depending on required number of open descriptors , for example a single MyIASM table could have 3 open descriptors. Will require system limits (ulimit -n) to be set for Linux Operating Systems. Ensure that innodb_open_files is not greater than this value. |