Recovering Modified Data

When a replacement data server or drive is available, you can restore the backup instance and recover the modifications. Two procedures are available.

• Example 1: To recover using a regular Block restore followed by copying only the modifications: Perform a regular Block restore, then perform a Windows command line copy of the modifications from the Instant Access mapped drive.

• Example 2: To copy everything from a Instant Access mapped drive: Perform a Windows command line copy of everything from the Instant Access mapped drive.

Example 1 has the advantage of limiting the amount of down time for the user. You can restore from the backup as soon as the new disk drive is available, while users continue to work via Instant Access. Then, when it is convenient, you take down the application and copy the modifications to the new disk. Example 2, on the other hand, requires the application to be down for the entire duration of the recovery.

Note. During the copy period, no modifications should be made to the data until the new drive is available to the application.

Considerations for Recovering Modified Microsoft Database Data

Instant Access is currently designed for uninterrupted file system access and backup verification. However, expert database administrators may want to adapt Instant Access for use as part of a protection strategy for applications, such as SQL and Exchange databases.

The copy procedures shown here are examples, designed to illustrate a basic approach and may not be directly applicable to the complexities of your environment. The examples are provided as a starting point. You would need to develop and carefully test your own procedures, based on knowledge of your particular database, system capabilities, and recovery requirements, including database synchronization. And, of course, it is important to continue to back up the secondary system itself. See Protecting Block Backups.

Example 1: To recover using a regular Block restore followed by copying only the modifications:

1. Follow the steps in Chapter 11: Block Restore to restore the Block backup using the management console. You can do this at any convenient time because it will not interfere with operations in the “live data” area.

2. Using Microsoft Disk Management, partition the new drive, and assign a drive letter to the new data area.

3. Stop the relevant application(s) on the recovery destination machine.

4. From the Microsoft Windows Command shell, use the xcopy utility with the /D option with no date. This copies only the modifications from the Instant Access mapped drive (the “live data” area).

   This is an example xcopy command:

   xcopy X: Y: /D [/S /Y]

   Note. The /D option with no date copies only those files whose source time is newer than the destination time. /S copies only files that are not empty. /Y suppresses prompting to overwrite an existing destination file.

   The new drive now has the current data.

5. Unmap the Instant Access mapped drive as described in Unmapping a Block Backup Instance from a Drive Letter.

6. Using Microsoft Disk Management, reassign the new drive letter if needed.

7. Restart the relevant application(s).

Example 2: To copy everything from a Instant Access mapped drive:

1. Using Microsoft Disk Management, partition the new drive, and assign a drive letter to the new data area.

2. Stop the relevant application(s) on the recovery destination machine.

3. From the Windows command line, use the xcopy utility to copy the Instant Access mapped drive to the new replacement server drive.

   This is an example xcopy command:

   xcopy X: Y: [/S /Y]

   The new drive now has the current data.

4. Unmap the Instant Access mapped drive as described in Unmapping a Block Backup Instance from a Drive Letter.
5. Using Microsoft Disk Management, reassign the new drive letter if needed.

6. Restart the relevant application(s).