Dynamic disk support (Windows only)

The following types of dynamic disks are supported in a Windows environment. This list of dynamic disks assumes that the dynamic disks are created and configured with Windows Disk Administrator:

• Simple volumes
• Spanned volumes
• Mirrored volumes
• Striped volumes
• RAID-5 volumes

For all supported Microsoft Windows, operating systems that restor a volume to dynamic disk require restoring the volume to a basic disk. After restore the volume to a basic disk, convert the disk to dynamic disk. You cannot restore a volume directly to a dynamic disk.

Backup considerations

During the snapshot of any dynamic disk other than a simple volume, there is the potential for increased memory utilization on the protected server. This increase might result in the snapshot not completing. This exposure exists when there are many data changes while the snapshot is running.

Backup success is based on the amount of memory available and the I/O load for Copy-On-Write (COW) when the snapshot runs on the protected server. If the I/O activity causes available memory limits to be exceeded, a FastBack Client system is limited to no more than 2 GB virtual address space (32–bit support limitation), the process terminates. The termination of a snapshot does not affect production I/O, but it does affect the Recovery Point Objective (RPO).

This exposure does not exist on volumes that are mapped to a single LUN (for example, basic disks or simple dynamic disks).

In addition, Continuous Data Protection is not supported for dynamic disks.

Restore considerations

Volume restore and instant restore are only possible to basic disks and to simple volumes that are used in supported operating system environments. Restoring a volume to dynamic disk requires restoring the volume to a basic disk. After you restore the volume to a basic disk, convert the disk to dynamic disk. You cannot restore a volume directly to a dynamic disk.

Regular bare machine recovery disks can be converted to dynamic disks by completing the following steps:

1. Log on as Administrator, or as a member of the Administrators group.
2. Open the Performance and Maintenance Control Panel, click Administrative Tools, and then double-click Computer Management.
3. In the navigation pane, click Disk Management.
4. In the pane that displays the disks, right-click the basic disk that you want to convert; then, click Convert to Dynamic Disk.
   Note: The disk title is on the left side of the Details pane. Right-click the gray area that contains the disk title.
5. If it is not selected, select the check box next to the disk that you want to convert. Click OK.
6. If you want to view the list of volumes in the disk, click Details.
7. Click Convert.
8. When prompted, click Yes.
9. Click OK.

If you remove one of the two disks in the software mirror, the remaining signature changes for the disk. If this result occurs, complete the following steps:

1. Delete the new chain.
2. In the history.txt file, replace old signatures with the new signature for all snapshots from the old chain. To get this number, right-click to select the remaining drive. Select Properties. The signature is displayed in the window.

Support for cluster environments

Microsoft Cluster Server (MSCS) does not natively support dynamic disks.

In the Veritas Cluster Server (VCS) environment, simple and spanned volumes are the only types of supported dynamic disks. The backup and restore considerations for dynamic disks apply in a VCS environment.

Veritas Storage Foundation for Windows provides a Cluster Option for MSCS. This option adds a cluster resource for dynamic disks to be used in an MSCS cluster. This configuration is not supported.

Dynamic disks that are created with Veritas Storage Foundation for Windows that are not in a cluster environment are not supported.