# oceanbase-cluster

Part of **OCEANBASE**

# OceanBase Database Management Console Guide

## Operations Overview

| Operation | Console Entry | Prerequisites | Description |
|----------|---------------|---------------|-------------|
| Connect Original Primary Cluster After Failover | Console > OceanBase > Clusters > Failover Management > Connect Original Primary Cluster | - Original primary cluster in maximum protection or maximum availability mode<br>- Standby cluster at same protection level<br>- Data consistency manually verified<br>- Original primary cluster restored and running | Reconnect the original primary cluster as a physical standby after a lossless failover |

## Step-by-Step Instructions

### Connect Original Primary Cluster After Failover

**Navigation**: Console > OceanBase > Clusters > Failover Management > Connect Original Primary Cluster

**Prerequisites**:
- The original primary cluster is in maximum protection or maximum availability mode
- The standby cluster is at the same protection level as the original primary cluster
- Data consistency between primary and standby clusters must be manually verified before failover
- The original primary cluster has been restored and is running

1. Restore the original primary cluster  
   - Element: **Restore Cluster** (button) — located in the top-right corner of the cluster management dashboard  
   - Notes: After restoration, the cluster automatically enters DISABLED state to prevent dual-primary conflicts.

2. Switch the original primary cluster to the standby role  
   - Element: **Convert to Physical Standby** (button) — located in the main content area under cluster actions  
   - Notes: This command must be executed via SQL client, not through the console UI. Use the SQL statement: `ALTER SYSTEM CONVERT TO PHYSICAL STANDBY`.

3. Enable synchronization from the new primary cluster to the original primary cluster  
   - Element: **Enable Synchronization** (button) — located in the new primary cluster's configuration panel  
   - Notes: System verifies data consistency during execution; if inconsistent, the operation fails. After successful execution, the original primary cluster becomes a synchronized physical standby.

**Form Fields**: None

## FAQ

Q: Where can I find the "Restore Cluster" button after a failover?  
A: The **Restore Cluster** button appears in the top-right corner of the cluster management dashboard once the original primary cluster is detected as offline or in a failed state.

Q: Can I perform the "Convert to Physical Standby" action directly in the console?  
A: No. Although the console displays the **Convert to Physical Standby** button for guidance, this step requires executing the SQL command `ALTER SYSTEM CONVERT TO PHYSICAL STANDBY` via a database client like ODC.

Q: What happens if data consistency is not verified before enabling synchronization?  
A: The **Enable Synchronization** operation will fail during the system’s internal consistency check. Ensure manual verification of log sequence numbers (LSNs) or SCN values before proceeding.

Q: Does the cluster remain usable while in DISABLED state after restoration?  
A: No. The DISABLED state prevents any write operations and blocks automatic promotion to avoid split-brain scenarios. The cluster must be explicitly converted to a physical standby before resuming replication.

Q: Do I need special permissions to perform these operations?  
A: Yes. You need administrative privileges on both the original primary and new primary clusters, including the ability to execute system-level ALTER commands and manage cluster roles.

## Pricing & Billing

### Billing Model
Per instance hour

### Price Reference
| Tier | Input Price | Output Price | Other Price |
|------|-------------|--------------|-------------|
| Standard | 0.05 / | 0.05 / | — |

### Free Tier
No free tier available

### Billing Notes
Billed based on actual runtime, with a minimum billing unit of 1 hour.