Note
For V4.4.1, this parameter is available starting with V4.4.1.
Description
log_storage_warning_trigger_percentage specifies the write performance percentage threshold that triggers a log disk failure.
Privilege requirements
Query the parameter
The
systenant and all user tenants can use theSHOW PARAMETERSstatement or theGV$OB_PARAMETERSview to query this parameter.Modify the parameter
Only the
systenant can modify this parameter. User tenants cannot modify this parameter.
Attributes
Attribute |
Description |
|---|---|
| Type | Int |
| Default value | 0 |
| Value range | [0, 50]. We recommend that you set this parameter to a value less than 10. |
| Modifiable | Yes. You can use the ALTER SYSTEM SET statement to modify the parameter. |
| Effective upon OBServer node restart | No. |
Considerations
The log disk failure detection algorithm continuously collects baseline data of the log disk write performance, monitors the current write performance, and compares it with the baseline performance. If the current write performance drops significantly compared to the baseline performance and does not recover within a certain period, the log disk is marked as failed.
The relationship between the
log_storage_warning_trigger_percentageparameter and the log_storage_warning_tolerance_time parameter is as follows:- If the value of
log_storage_warning_trigger_percentageis 0, performance data is not collected. If the log write delay exceeds the value of thelog_storage_warning_tolerance_timeparameter, the log disk is marked as failed. - If the value of
log_storage_warning_trigger_percentageis greater than 0, the log disk is marked as failed if the current write performance drops to the baseline performance multiplied by the percentage specified by thelog_storage_warning_trigger_percentageparameter and the performance degradation lasts for the time specified by thelog_storage_warning_tolerance_timeparameter. - The
log_storage_warning_trigger_percentageparameter specifies the write performance percentage threshold that triggers a log disk failure. A larger value makes the failure detection algorithm more sensitive. Thelog_storage_warning_tolerance_timeparameter specifies the duration of performance degradation. A larger value makes the detection algorithm more robust.
- If the value of
Examples
Set the write performance percentage threshold for the log disk failure detection algorithm to 5 and the performance degradation duration threshold to 3s. If the log disk write performance drops to 5% of the baseline performance and the duration is 3s, the log disk is marked as failed.
obclient> ALTER SYSTEM SET log_storage_warning_trigger_percentage = 5;
obclient> ALTER SYSTEM SET log_storage_warning_tolerance_time = '3s';