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Windows instance volume issue

This document addresses the causes of issues when using Microsoft Windows instances and provides solutions.

Additional volume in offline status on instance​

When additional volumes are attached to a Windows instance and the instance is Shelve/Unshelve, the Disk Management utility may display the message: The disk is offline due to a policy set by an administrator. This occurs because the Windows operating system sets newly attached disks to offline status based on the default SAN Policy. As a result, the OS does not mount the disk.

SAN Policy (SCSI Availability Notification Policy) is a Windows policy that determines whether newly connected disks are automatically switched to online status. By default, the setting is Offline Shared, designed to prevent disks available to multiple hosts in shared environments from being automatically mounted.

▶️ Solution

  1. Check SAN Policy: Use the diskpart command to check the current SAN Policy settings.

    Check SAN Policy using CMD
    C:>diskpart

    DISKPART> SAN
    SAN Policy : Offline Shared

    The result Offline Shared indicates that disks are set to offline by default.

  2. Change SAN Policy: Set SAN Policy to OnlineAll to ensure that disks are automatically set to online status. Changing the SAN Policy to OnlineAll prevents issues related to additional volumes by automatically putting newly attached disks online.

    Change SAN Policy
    C:>diskpart

    DISKPART> SAN POLICY=OnlineAll

  3. Manually change offline volumes to online: For volumes already in offline status, manually switch them to online. Refer to Attach volume on Windows for guidance on making the attached volume online.

    1. Open the Windows Disk Management utility.
    2. Select the disk displayed as offline and click [Change to online].

    Windows volume offline

    info

    If the additional volume is set to online manually during the initial connection, the same issue will not recur.