Administrators can also initiate a planned failover from the Windows Admin Center to migrate workloads from an active site to a secondary site. A planned failover can be beneficial when a scheduled maintenance window or approaching natural disaster has the potential to negatively affect running workloads on the active site. The Switch Direction feature of Windows Admin Center allows administrators to move workloads from one site to another in a stretched cluster configuration. This feature must be initiated on a per-volume basis.
We performed a Switch Direction operation on the OM volume, which hosted the OME-1 VM virtual disk. The two main goals of this test were as follows:
The following figures depict the healthy VMs, healthy volumes, and the Storage Replica partnerships, respectively, in Windows Admin Center before the Switch Direction operation was initiated.
A device discovery job was created in the OMEnt portal. The following figure depicts the running job in progress before the Switch Direction operation was initiated.
The Switch Direction operation was initiated from the Storage Replica tool in Windows Admin Center. We selected only the partnership involving OMEnt, which consisted of OM-group and OM-replica-group, for planned failover. After selecting the partnership, we selected Switch direction from the drop-down menu, as shown in the following figure:
Within seconds, Owner Node for the OM and OM-Log volumes changed to Node 2 in Site 2, and Owner Node for the OM-Replica and OM-Replica-Log volumes changed to Node 2 in Site 1, as shown in the following figure. During this operation, we observed no interruption while accessing the OMEnt web application from a client device.
The following figure shows that the OMEnt discovery job was still progressing throughout the Switch Direction operation.
At this time, the OME-1 VM was running in Site 1, but its virtual disk that resided on the OM volume was running in Site 2. Performance problems can result because I/O is traversing the replication links across sites. After approximately 10 minutes, a Live Migration of the OME-1 VM would occur automatically so that the VM would be on the same node as its virtual disk. To speed up the process and avoid a potential degradation in performance, we manually initiated a Live Migration in Failover Cluster Manager.
As with the unplanned failover test scenario, an IP address change was required after the Live Migration because the VM networks in both sites are on separate L3 subnets. However, the Live Migration presented an additional challenge because the VM was never restarted. Thus, the VM would not request an IP address from the DHCP server in the new subnet. To avoid this issue in the lab, we took these steps:
These actions produced the following behavior from OMEnt: