Written by: Murray White - Solution Architect with Vision Solutions


This is a demonstration of how Double-Take Availability migrates data from an EMC-based volume to an EqualLogic based-volume.

In some circumstances, a customer may want to update their storage from EMC to EqualLogic storage without necessarily migrating the server itself. This article focuses on this scenario.
Double-Take Availability works at the Operating System level and allows the user to synchronize data from one volume to another from within the confines of the OS. This article focuses on a source volume being an EMC-based volume and the target volume an EqualLogic-based volume. Double-Take is however agnostic of the underlying storage. So, the information contained in this demonstration also applies for other storage types (ie: migrating from non-Dell storage to Dell storage, MDxx storage to EQL storage, EMC storage to Compellent storage, and so on…)
Additionally, you should note that storage can be local (DAS), or SAN-attached to the server. This example of EMC-EQL represents an EMC Fibre-attached volume and an EQL iSCSI attached volume.
To summarize, Double-Take Availability will replicate/mirror data from/to volumes where those volumes are considered physical logical drives to the Windows OS that Double-Take is installed to. The volumes can be local/direct attached, Fibre-attached, or iSCSI attached.
Double-Take Availability provides two mechanisms to achieve data migration from volume to volume.
1) Data synchronization and replication from drive-to-drive.
2) Failover of Windows Shared folders (if applicable)

Data synchronization and replication from drive-to-drive
Double-Take can replicate individual files, folders or all files and folders on a volume. Replication is byte-level and asynchronous. NTFS permissions/ACLs are captured and replicated as part of the replication process as well as the file/folder structure of the data.

Failover of Windows Shared folders (if applicable)
In addition to data synchronization and replication, Double-Take Availability can capture and replicate the Windows Shared folders from a protected volume and apply the Shares to the target destination volume. This process is considered “failover” and is managed via the Double-Take Failover Control Center.

Source Server / Volumes

We have a Dell R710 PowerEdge server running Windows 2008 R2 Enterprise.
C:\ contains the Operating System and other System-State (Program Files, User Profiles, etc)
H:\ is an EMC-based volume. It is attached to the server using Fibre channel via a HBA.
The data on this volume will be migrated to the EQL-based volume.
G:\ is the EQL-based volume… a PS6000XV device. It is attached to the server using iSCSI via iSCSI Initiator.

Target Server
There is no separate target server for this demonstration, as we are moving data volume-to-volume on the same server. The source server is therefore both a source and target.

Please take a moment to view the following video. It is a live demonstration of the data migration process.
The video walks through the process of configuring Double-Take Availability for the data migration.