Account for fault-domain alignment when reattaching Premium SSD v2 disks

Source facts

In supported nonzonal regions, attaching a Premium SSD v2 disk across fault domains can trigger a background move to align storage with the VM. Only one copy can run per disk; reattachment, expansion, and customer-managed-key changes face documented restrictions during alignment. OptimizedForFrequentAttach skips alignment copies on future attachments. Changing that property on an attached disk first requires detaching it. Microsoft Learn.

Applicability

Confirm regional eligibility and required subscription registration before reviewing this behavior. Identify the disk, destination VM, availability set, and any copy already underway. Distinguish a fault-domain alignment copy from background creation from a snapshot; check the applicable restriction before retrying an operation.

DSE recommendation

Review fault-domain copy status before repeated reattachment, expansion, or customer-managed-key changes. For workloads that frequently move disks, have the storage and availability owners decide whether skipping future alignment is acceptable. Document that decision as a change in alignment behavior, not a switch that merely makes the same placement finish faster. Schedule any necessary detachment with the application owner.

Verification

Observe a controlled attachment and reconcile the resulting copy state with the requested follow-up operation. For an approved frequent-attach design, verify the disk property and actual subsequent behavior on a test workload. Preserve disk and VM identifiers, fault-domain context, and measured outcomes. Avoid repeated detach/attach attempts while the documented copy restriction remains unresolved, and confirm application recovery after the authorized move.

Official references

Microsoft Learn: Premium SSD v2 with availability-set VMs. Source reviewed September 9, 2026.