Reinstating faulted hardware
Once a failure occurs and an application is migrated to another node or site, it is important to know what will happen when the original hardware is reinstated.
Refer to the failure scenarios:
For the failure scenarios 3 through 7 in this section, the following table lists the behavior when various hardware components affecting the configuration (array or disks, site hardware, networking cards or cabling, storage interconnect, etc.) are reinstated after failure. Situations 1 and 2 have no effect when reinstated. Keep in mind that the cluster has already responded to the initial failure as indicated in the previous table.
Related information
Table: Behavior exhibited when hardware is reinstated
| Failure situation before reinstating the configuration | ForceImport set to 0 | ForceImport set to 1 |
|---|---|---|
| (import not forced) | (automatic force import) | |
| 3. Failure of disk array or all disks | No interruption of service. Resync the mirror from the remote site. | Same behavior |
| May mean that a power cord was unplugged, a system hang occurred, or another failure caused the system to stop responding. | ||
| 4. Site failure | Inter-node heartbeat communication is restored and the original cluster node becomes aware that the application is online at the remote site. Resync the mirror from the remote site. | Same behavior |
| All access to the server and storage is lost. | ||
| 5. Split-brain situation (loss of both heartbeats) | No interruption of service. | Same behavior |
| 6. Storage interconnect lost | No interruption of service. Resync the mirror from the original site. | Same behavior |
| Fibre interconnect severed. | ||
| 7. Split-brain situation and storage interconnect lost | No interruption of service. Resync the mirror from the original site. | VCS alerts administrator that volumes are online at both sites. Resync the mirror from the copy with the latest data. |
While the outcomes of using both settings of the ForceImport attribute for most scenarios are the same, the ForceImport option provides automatic failover in the event of site failure. This advantage comes at the cost of potential data loss if all storage and network communication paths between the sites are severed. Choose an option that is suitable given your cluster infrastructure, uptime requirements, and administrative capabilities.