Recovery procedures for service group dependencies
Service group dependencies have special requirements and limitations for disaster recovery configuration and for actions to be taken in a disaster recovery scenario.
The procedure and requirements for bringing service group dependencies online at the secondary site depends on their configuration: soft, firm, or hard.
In general, if a child or parent remains online at the primary site, you take it offline before you bring the child and parent service groups online in the correct order on the secondary site.
An exception is the RVG service group, used for Volume Replicator replication, which the wizard creates with an online, local, hard dependency. The RVG group remains online at the primary site in all cases and should be left online at the primary site.
The following tables show the recovery requirements if a child or parent service group fails at the primary site and is unable to fail over on the primary site, thus requiring the secondary site to be brought online.
Using a scenario of a parent and one child, the following table shows the expected results and necessary actions you must take for an online, local, soft dependency link.
Related information
Table: Online, local, soft dependency link
| Failure condition | Result | Action required (sequentially) |
|---|---|---|
| The child service group fails | - The parent remains online on the primary site. | - Primary site: Manually take the parent service group offline at the primary site. Leave the RVG group online. |
| - An alert notification at the secondary site occurs for the child service group only. | - Secondary site: Bring the parent and child service groups online in the appropriate order (child first, then parent). | |
| - The RVG group remains online. | ||
| The parent service group fails | - The child remains online on the primary site. | - Primary site: Manually take the child service group offline at the primary site. Leave the RVG group online. |
| - An alert notification at the secondary site occurs for the parent only. | - Secondary site: Bring the service groups online in the appropriate order (child first, then parent). | |
| - The RVG group remains online. |
Using a scenario of a parent and one child, the following table shows the expected results and necessary actions you must take for an online, local, firm dependency link.
Table: Online, local, firm dependency link
| Failure condition | Result | Action required (sequentially) |
|---|---|---|
| The child service group fails | - The parent goes offline on the primary site. | Secondary site: Bring the service groups online in the appropriate order (child first, then parent). |
| - An alert notification at the secondary site occurs for the child service group only. | Leave the RVG group online at the primary site. | |
| - The RVG group remains online. | ||
| The parent service group fails | - The child remains online on the primary site. | - Primary site: Manually take the child service group offline at the primary site. Leave the RVG group online. |
| - An alert notification at the secondary site occurs for the parent only. | - Secondary site: Bring the service groups online in the appropriate order (child first, then parent). | |
| - The RVG group remains online. |
Using a scenario of a parent and one child, the following table shows the expected results and necessary actions you must take for an online, local, hard dependency link.
Table: Online, local, hard dependency link
| Failure condition | Result | Action required (sequentially) |
|---|---|---|
| The child service group fails | - The parent goes offline on the primary site. | Secondary site: Bring the service groups online in the appropriate order (child first, then parent). |
| - An alert notification at the secondary site occurs for the child service group only. | Do not take the RVG group offline at the primary site. | |
| - The RVG group remains online. | ||
| The parent service group fails | - The child remains online on the primary site. | - Primary site: Manually take the child service group offline at the primary site. Leave the RVG group online. |
| - An alert notification at the secondary site occurs for the parent only. | - Secondary site: Bring the service groups online in the appropriate order (child first, then parent). | |
| - The RVG group remains online. |