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When running workloads on virtual machines on the PowerStore X appliance or AppsON mode, there are some important considerations when sizing workloads.
General VMware tuning and resource allocation principles apply; consult the VMware article About vSphere Resource Management for general tuning guidelines. If resources in the vSphere cluster become a bottleneck, guest storage performance will suffer, reducing the effectiveness of running workloads in AppsON mode.
PowerStore X appliances reserve approximately half the CPU and memory resources for running PowerStore appliance tasks. When sizing workloads to run on the appliance, this needs to be considered. This reservation is visible in vSphere as the CPU and memory will be displayed as consumed by the PowerStore X controller virtual machines. Also the ESXi cluster cannot run at 100% capacity without incurring degraded performance. A minimal amount of resources are required for ESXi overhead. See the VMware articles Configuring Resource Allocation Settings and Administering Memory Resources for resource reservation and sizing guidance.
For production applications where guaranteed performance is necessary, make sure to size for possible node failover in the PowerStore cluster.
General best practices apply when running SQL Server virtual machines in AppsOn mode, but there are two items to note. First, VMware vVols will typically be used as storage for VMDKs. While other storage options are still available, PowerStore X is optimized for vVols storage, so this option should be the first choice. Also, use the VMware Paravirtualized SCSI (PVSCSI) Controller as the virtual SCSI Controller. The PVSCSI controller improves performance and reduces CPU overhead.
For more best practices guidance for running SQL Server virtual machines, see the VMware guide Architecting Microsoft SQL Server on VMware vSphere.
Starting with PowerStoreOS 2.0, up to four PowerStore X appliances can be added to a PowerStore X cluster. Then, AppsOn workloads can be moved among appliances in the PowerStore X cluster using VMware vSphere vMotion. When moving virtual machines among appliances in an AppsOn cluster, the storage will not be migrated because PowerStore Storage Containers are presented as a vVols datastore across all appliances in the cluster. However, the vVols do reside on a single appliance. Therefore, this must be considered when migrating VMs between clustered appliances. For a VM, running the compute on one appliance when the vVols reside on another appliance will result in degraded performance.
In the following Compute > Virtual Machines view, a VM is running on PS-9-appliance-1-node-B.
Examining the vVols that belong to this VM shows that they are on PS-9-appliance-2. These vVols should be migrated to PS-9-appliance-1. This process is done by selecting a volume and then selecting Migrate. This action can also be done in the PSTCLI using the migration_session create command.
Once the migration has been started, it can be viewed in the Migration section.