datafile_disk_percentage|V4.6.0|OceanBase Database| docs|Distributed Database

This parameter is available starting with V2.2.50.

Description

In Shared-Nothing (SN) mode, the datafile_disk_percentage parameter specifies the percentage of the total disk space occupied by data files (data_dir is the disk that OceanBase Database initializes for data storage).
In Shared-Storage (SS) mode, the datafile_disk_percentage parameter specifies the percentage of the total disk space occupied by local cache space.

Query the parameter

The sys tenant and all user tenants can query this parameter by using the SHOW PARAMETERS statement or the GV$OB_PARAMETERS view.
Modify the parameter

Only the sys tenant can modify this parameter. User tenants cannot modify this parameter.

Attribute	Description
Type	Int
Default value	0 Note Starting from V4.0.0, the default value is changed from 90 to 0.
Value range	[0, 99] Note Starting from V4.0.0, the value range is changed from [5, 99] to [0, 99].
Modifiable	Yes. You can use the `ALTER SYSTEM SET` statement to modify the parameter.
Effective upon OBServer node restart	No. The setting takes effect immediately.

When the value of this parameter is 0, the system automatically calculates the percentage of the total disk space occupied by data files (in SN mode) or local cache space (in SS mode) based on whether the log and data share the same disk:
- If they share the same disk, the percentage is 60%.
- If they do not share the same disk, the percentage is 90%.
When this parameter and the datafile_size parameter are both configured, the value of datafile_size takes precedence. For more information about the datafile_size parameter, see datafile_size.

In SN mode, set the percentage of the total disk space occupied by data files to 90%.

obclient> ALTER SYSTEM SET datafile_disk_percentage=90;