Dell PowerStore Importing External Storage to PowerStore Guide

Failures during agentless import

Some failures might be intermittent in nature, for example, due to the load of the system or network. Usually, if the import attempt is not successful, the I/Os are not affected and they continue with the source volumes. A simple retry of the import should suffice. Sometimes, the resolution of network or load issues is required before retrying the import. When an import fails, the error message attempts to indicate what went wrong without getting too technical. If repeated attempts to resolve the issue fail, contact your service provider.

If the destination loses back end connection with the source system in the SAN path during an agentless import, the import changes to the Cancel Required state. It is possible that the errors between the PowerStore cluster and the source network result in I/O errors to a user application. When import changes to the Cancel Required state, an alert is raised to reconfigure the user application to use the source volume. After reconfiguring the user application to use the source volume, cancel the import session manually. Import can be retried after the SAN paths from the PowerStore cluster to the source system issues are resolved.

PowerStore is a dual-node, multi-appliance scale-out cluster. Typically, most failures are not fatal and are handled by the inherent PowerStore high availability design. The import orchestrator runs inside the PowerStore appliance and is as highly available as the PowerStore appliance. However, should there be an extreme case where a PowerStore cluster goes down during import before cutover, reconfigure the user application back to the source system. If the entire appliance is down, both nodes of the appliance are down. However, in a multi-appliance cluster, ongoing imports continue in other running appliances. The imports, for which the destination volume is on that specific appliance which is down, stall. In this case it is recommended that the appliance be brought up first before trying to cancel the stalled session.

In case of a PowerStore node failure during import, both import and I/Os are not impacted. The other node takes over. If import is not able to continue, it changes to the Cancel Required state. When import changes to this state, an alert is raised to reconfigure the user application to use the source volume. After reconfiguring the user application to use the source volume, cancel the import session manually.

Sometimes, the node recovery time might be long and host I/Os might experience latency issues. In worst cases, the I/O timeout expires, leading to temporary data unavailability. If the node cannot reboot or the recovery of the node is taking too long, reconfigure the user application back to the source array. Recovery for such cases occurs once the node that went down recovers fully. Once the PowerStore node has recovered and PowerStore is healthy, try importing again. If the issue persists, contact your service provider.