Avamar: How to restore an Exchange database from a backup affected by the Database path case-mismatch issue.

Objective:

• Restoring an Exchange database from an Avamar backup affected by the database's path case-mismatch issue described in Avamar: Exchange database restore failing with avtar error stating database not found in backup
• This workaround is used to restore an exchange database from a backup that was created before the application of the flag "--use-case-sensitive-paths"
• It uses the avtar.exe binary in an elevated command prompt

• If the backup intended to be restored was taken within the past seven days (on rare occasions), go to the "Addition Info" section and follow the instructions.

Workaround Prerequisites:

1. The system from where the avtar.exe is launched must have the Avamar Windows client registered against the same Avamar server where the backup is located. The Exchange plug-in is not required for this workaround.
2. The Windows command prompt must be opened as administrator (elevated command prompt), the user account must have the local admin privilege of the system.
3. The credentials for the Avamar MCUser (or any other Avamar user with restore privilege) are required.
4. The Avamar backup client full path, backup label number, and the database full path are required.
5. The destination drive must have sufficient free disk space to hold the databases and log files related to the restore (an example of space calculation is provided below).

Command Syntax: 

avtar.exe -x --internal --incpartials --status=60 --nostdout --debug --server=<IP/FQDN> --id=MCuser --ap=<password> --path=<domain/client> --labelnum=<label> --logfile=<Log path> --target=<Destination Path> <DB path to be restored without the mismatched section of the path> 

• The client full path for the option "---acnt" is case-sensitive, it can be found in the backup log (avtar or .alg log file), see the example:

    <flag type="string" value="/clients/Exchange/EX-Node1.Dell.com" name="path" />

• The backup label number can be seen directly from the restore section in the Avamar User interface (GUI or AUI).
• For the last item of the command <item path to restore>, open the backup log (if still available in the /var folder) and search for the "targetlist" section, in there, identify the full path of the database required for restore, see example for "database4":

  <targetlist>
    <view>
      <dir internal="true" labelnum="158" fullname="EX-Node4_00000000/H:/MountPoint/Database6" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="159" fullname="EX-Node4_00000000/C:/Program Files/avs/var/backupMetadata" acnt="/clients/Exchange/EX-Node1.Dell.com" />      
      <dir internal="true" labelnum="155" fullname="EX-Node3_00000000/H:/MountPoint/database5" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="155" fullname="EX-Node3_00000000/H:/mountpoint/database4" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="156" fullname="EX-Node3_00000000/C:/program files/avs/var/backupmetadata" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="157" fullname="EX-Node2_00000000/H:/MountPoint//Database3" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="158" fullname="EX-Node2_00000000/H:/MountPoint/Database2" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="159" fullname="EX-Node2_00000000/C:/Program Files/avs/var/backupMetadata" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="158" fullname="EX-Node1_00000000/H:/MountPoint/Database1" acnt="/clients/Exchange/EX-Node1.Dell.com" />
      <dir internal="true" labelnum="159" fullname="EX-Node1_00000000/C:/Program Files/avs/var/backupMetadata" acnt="/clients/Exchange/EX-Node1.Dell.com" />
    </view>
  </targetlist>

• If the backup log is no longer available in the /var directory, use the instructions "Retrieving an Avamar backup log from the server" under "Additional Info" of the article Avamar: How to gather logs to troubleshoot backup and restore issues
• For this example, the path would look like this:

  • EX-Node3_00000000\H:\mountpoints\Database4\Database4.edb

• However, since the "case capitalization mismatch" issue is at the "mountpoints" level, using this full path would result in the known restore failure "Database not found in backup"
• To work around this restore issue, the path is cut from the level immediately to the left of the area of mismatched "mountpoints". For this example, the path used in the command is this:

  • EX-Node3_00000000\H:\

• The result of this workaround is the restoration of any Exchange database including transaction logs (if they are in the same path under H: Drive) that were hosted on the Exchange node "EX-Node3" at backup time.
  • This would require sufficient free disk space on the system where the command is run to accommodate all the Databases and Transaction logs present on "EX-Node3" at the time of backup.
  • For example: If the entire backup size was 3 TBs, it would not necessarily require 3 TBs of free space for the restore: 
    • It only requires the size of all the DBs+Logs that are restored from the node "EX-Node3"
    • For instance, it must have 400 GBs instead of 3TBs, the size of databases 4 and 5 along with their corresponding logs
    • The disk space must be calculated on case by case

Workaround Steps:

1. Prepare the command in a notepad with the correct information (if the logfile or target values contain spaces it must be in double quotes)
2. Open the Windows command prompt in elevated mode
3. Move to the folder where the binary "avtar.exe" is located, default location "C:\Program Files\avs\bin\"
4. Run the pre-filled command, see the example below

avtar.exe -x --internal --incpartials --status=60 --nostdout --debug --server=192.168.20.105 --id=MCUser --password=******** --account=/clients/Exchange/EX-Node1.Dell.com --labelnum=163 --logfile=D:/Restore_logs/Restore_163_Database4_30-08-2024.log --target=E:/Restore_Temp EX-Node3_00000000/H:/ 

5. Wait for the command to complete (the prompt is returned). Depending on the data size to be restored, it may require a few minutes or several hours
6. Once the command is completed, verify that the Exchange DBs are correctly restored along with their respective transaction logs
7. If any issue is found during the process, review the restore log files, as per example "D:/Restore_logs/Restore_163_Database4_30-08-2024.log".
   • If further assistance is required, contact the Avamar support team using the Service Request process

Post Restore task:

• If the restoration is successful, it is expected to see the restored database in "Dirty Shutdown" state.
• This is because the transaction log files have not been replayed yet to the database.
• To replay the logs follow this article Avamar: How to recover an Exchange database from the "Dirty Shutdown" state

• If the backup intended to be restored was taken within the past seven days, immediately contact the Avamar support team using the Service Request process. (Rare occasions)
• Mention that this article was read and provide its reference to the support team.
• The Avamar support team helps with the recovery using a slightly different restore procedure, yet a more efficient one.