Increase log disk capacity
This topic describes how to increase the log disk capacity. Increasing the log disk capacity is a whitelist feature. To use this feature, contact ApsaraDB OceanBase technical support.
Background information
OceanBase databases use a separate log disk to store transaction logs, called OceanBase Commit Logs (clogs). This mechanism is similar to the redo log in MySQL. Clogs ensure the atomicity, durability, and isolation of transaction processing. They also provide high availability. In a distributed architecture, multiple database replicas use the Paxos protocol to sync clogs and ensure strong data consistency.
If the log disk runs out of capacity, the system cannot generate and write log information for new transactions. This prevents these transactions from being committed. In addition, frequent disk space alerts and constant attempts by the system to clean up logs create extra input/output (I/O) load. This load can slow down the overall system performance and response speed. To prevent risks such as data integrity damage, transaction processing interruptions, and performance degradation, increase the log disk capacity in advance. This ensures data security and the stability of transaction processing.
When the stored log information reaches its storage limit, the oldest data is deleted first.
Increasing the log disk capacity does not affect your services. However, to ensure service stability, perform this operation during off-peak hours.
Prerequisites
Before you increase the log disk capacity, ensure that the following conditions are met.
The cluster is in the Running state.
All tenants in the cluster are in the Running state.
The cluster is not using temporary capacity.
The storage class of the cluster is cloud disk.
Procedure
Log on to the OceanBase console .
In the navigation pane on the left, click Instance List.
In the instance list, find the target cluster instance and click its name to go to the Cluster Instance Workspace.
In the upper-right corner, click the More icon and select Standard Upgrade/Downgrade.
Click Scale Out Log Disk.
NoteOceanBase databases do not support scaling in log disks. After you scale out a log disk, you cannot reduce its capacity.
On the purchase page, set Log Disk Size and select Terms of Service. For more information about billing rules, see Pricing.
Click Buy Now.
What to do next
After you scale out the disk, go to the cluster workspace to view the current log disk specifications.