> For the complete documentation index, see [llms.txt](https://docs.tessell.com/tessell/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tessell.com/tessell/database-engines/tessell-for-mysql/db-services/readme-mysql/homepage-mysql/instances-mysql.md). # Instances The Instances tab displays all configured instances for your MySQL database service in a table, with per-instance details and switchover actions. *** ## What instance topologies does Tessell support for MySQL? | Instance type | Description | | -------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Single instance** | Database service with one instance in a given region and availability zone. | | **Multi-AZ (HA)** | Database service with one primary and one or two synchronous failover replica(s). Instances must be in the same region, but can be in the same or a different availability zone as the primary. Failover replicas are always homogeneous (infrastructure, parameters, storage, IOPS, and so on). All planned operations run in rolling mode to minimize downtime. | | **Disaster Recovery (DR)** | Asynchronous replica instances that can be added in the same or a different region as the primary. Multiple DR instances can be added to a service. No automatic failover support. Can be added to both single-instance and Multi-AZ services. | | **Read Replica (RR)** | An asynchronous replica opened in read-only mode. Use for read-only queries. | *** ## How do I add a DR or Read Replica instance? * To add a Disaster Recovery instance, see [Adding Disaster Replica](/tessell/database-engines/tessell-for-mysql/db-services/adding-disaster-replica.md). * To add a Read Replica, see [Adding Read Replica](/tessell/database-engines/tessell-for-mysql/db-services/adding-read-replica.md). As an alternative, use the **Code** button to add the instance: 1. Click the **Code** button in the top-right corner to view the **Code for Add New Instance** window. 2. On the left, view the API, its type, and the payload. 3. On the right, view the code to create instances in Shell, Python, Go, Java, JavaScript, and PowerShell. 4. Use the copy and download buttons to save the code. 5. Click **Close** to return to the main window. *** ## What columns appear in the Instances table? | Column | Description | | ----------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Name** | Auto-generated in incremental order: `default-node-0` (primary), `default-node-1` (replica 1, typically an HA replica configured for automatic failover), `-node-` (replica 2 onwards — the digit starts at 0 for a new Read Replica or DR replica and increases with the number of nodes configured). | | **Status** | Current instance state (see table below). | | **Role** | Primary, HA Replica (Automatic Failover), Read Replica (RR), or Disaster Recovery (DR). Shows the server name below the role. | | **Server** | Server where the instance is deployed. Click the server name to open its home page in the Servers app. | | **Region/Zone** | Cloud provider and region hosting the instance. | | **Parameter Profile** | Parameter profile applied at provisioning. | | **Compute** | Compute shape with vCPU and memory details below. | | **Created** | Date and time the instance was created. | | **Storage** | Storage size specified at provisioning; click **See details** for storage provider, throughput, and IOPS. | | **Connection Endpoint** | Hostname for the instance; click **See Details** for Service URL, Host, Port, and Username. | ### Instance status reference | Status | Description | Actions allowed | | -------------------------------------- | --------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- | | **UP** | Instance is running and accepting connections. | Resize compute/storage, update parameter profile, delete (Read Replica or DR only) | | **DOWN** | Instance is down. | Raise a Tessell support ticket if the instance needs to be revived | | **STOPPED** | Instance is not running and is completely stopped. | Start the service | | **CREATING** | Provisioning is in progress, or a new instance is being added to the service. | No actions allowed | | **DELETING** | Deletion in progress. Only Read Replica and DR instances can be deleted from a service. | No actions allowed | | **REBUILDING** | Compute or storage resize is triggered for the instance. | No actions allowed | | **REBUILD\_FAILED** | Compute or storage resize was triggered and did not complete. | All actions allowed | | **PATCHING** | Available patches are selected to apply for the database service. | No actions allowed | | **PATCH\_FAILED** | Patching for the database instance has failed. | All actions allowed | | **UPDATING\_PARAMETER\_PROFILE** | Parameter profile update is triggered for the instance. | No actions allowed | | **PARAMETER\_PROFILE\_UPDATE\_FAILED** | Parameter profile update failed. | All actions allowed | > **Note:** Using the ellipsis icon on individual instance rows, you can create, update, or delete private links for DR and RR nodes separately. Creation of private links for DR and RR nodes is currently supported for **AWS cloud only**. *** ## How do I switch over to a replica? | Target replica | For more information | | ------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Failover (HA) replica** | See [Switchover to Failover Replica](/tessell/database-engines/tessell-for-mysql/db-services/multi-az-deployment-for-mysql.md#switchover-in-multi-az-deployment). | | **DR replica** | See [Switchover to DR Replica](/tessell/database-engines/tessell-for-mysql/db-services/switchover_to_dr.md). |

Figure 1 — Instances tab

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