Inactive and Detached Managed Disk

Some may be intentionally retained for reattachment, backup, or migration purposes, but many persist unintentionally due to the lack of automated cleanup processes. When these detached disks are also inactive-showing no read or write activity-they represent unnecessary ongoing costs. Identifying and removing these orphaned disks can produce meaningful savings without affecting any active workloads.

Managed Disks are billed based on:

• Provisioned disk size (per GB/month) - billed regardless of attachment or usage
• Disk types include:
• Premium SSD (v1/v2) - High-performance workloads
• Standard SSD - Balanced cost and performance
• Standard HDD - Lower-cost for infrequent access
• Ultra Disk - Provisioned with specific IOPS and throughput, billed separately
• Snapshots - Billed separately based on storage consumed

Unattached disks are fully billable until explicitly deleted

• Identify Managed Disks that are in an unattached state (not linked to any VM)
• Review metrics or activity logs to determine whether the disk has seen any read or write operations during the lookback period
• Check whether the disk is intentionally retained for recovery, migration, or reattachment
• Determine whether a snapshot has already been created or is needed prior to deletion
• Consult with workload owners or infrastructure teams to verify whether the disk still serves a business or technical purpose

Delete inactive and detached Managed Disks that are no longer needed. If data retention is required, create a snapshot before deletion. Establish periodic reviews or automate cleanup of unused resources to reduce persistent storage costs, especially for higher-tier disk types.

• Azure Managed Disks Pricingazure.microsoft.com
• Azure Disk Storage Overviewlearn.microsoft.com