Overview:

Enterprise Vault (EV) Discovery Accelerator (DA) version 8.0 introduced the Analytics feature that allows additional work to be automated against accepted search results.  When Analytics is enabled for a DA Case or Research Folder, a full text index folder is created to contain information about the items that are processed.  This folder is named "DataFullTextIndex_Case_1", where Case is the name of the DA Database and the 1 is the actual CaseID of the Case or Research Folder under which the Analytics feature was enabled.

When SQL Server backup is used to backup the DA database, the backup process also backs up the "DataFullTextIndex_Case_1" folder and associated .ndf file.  Should this folder or file be missing, moved or renamed, which testing has shown to only occur if the SQL services are stopped, the backup will fail with the above error in the SQL Server's ERRORLOG, or with the following error in a pop-up alert if running the backup manually from the Microsoft SQL Server Management Studio console:

Backup failed for Server 'EV7SQL'. (Microsoft.SqlServer.Smo)
Additional Information:
System.Data.SqlClient.SqlError: The backup of full-text catalog
'DataFullTextIndex_Case_1' is not permitted because it is not online. Check errorlog file for
the reason that full-text catalog became offline and bring it online.  Or BACKUP can be performed by using the FILEGROUP or FILE clauses to restrict the selection to include only online data.
(Microsoft.SqlServer.Smo)"

The SQL Server's Application Event Log may also contain the following entry:
Source:    MSSQLSERVER
Category:  (6)
Type:      Error
Event ID:  3041
Description:
BACKUP failed to complete the command BACKUP DATABASE Case.  Check the backup application log for detailed messages.
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

If the 'DataFullTextIndex' folder or .ndf file was renamed, then renamed back to its original name, or deleted and restored, or moved to another location (i.e., folder or drive), the above errors will continue to be thrown and the backup will fail.

Solutions:
This issue has two possible solutions.  Solution 1 should work to resolve all instances of this issue.  Solution 2 will work if the Case or Research Folder has not been deleted and detaching the database is not desired.

Solution 1:
If the issue occurs and the associated Case or Research Folder has been deleted, this is the solution to use.  If the associate Case or Research Folder is still open or closed, this or Solution 2 can be used.
1) Stop the Enterprise Vault Accelerator Manager Service (EVAMS) on the DA server
2) Open SQL Server Management Console on the SQL Server, if not already open, using an account with proper permissions to access and modify the DA Customer database (i.e., the Vault Service Account)
3) Expand the Databases in the left panel
4) Right click on the DA Customer database
5) Select Tasks, then the 'Detach...' option
6) Click the check box for 'Drop Connections' to add a check mark for that option in the pop-up that displays
7) Click the OK button to complete the database drop operation
8) As soon as the database is dropped, the SQL Server Management Console will refresh to show the database no longer listed
9) Right click on the Databases level
10) Select the 'Attach...' option
11) Click the 'Add,,,' button associated with the Databases to attach: section in the top half of the Attach Databases pop-up pane
12) An alert may pop-up titled "Locate Database Files - SQLServer", with the context "C:\SQLData  Cannot access the specified path or file on the server.  Verify that you have the necessary security privileges and that the path or file exists.  If you know that the service account can access a specific file, type in the full path for the file in the File Name control in the Locate dialog box."  Click the OK button to accept this information.
13) The Locate Database Files - SQLServer pop-up will be displayed with the tree structure for the SQL Server's disk drives displayed.
14) Expand the tree structure on the drive and folder that contains the database's MDF file, then select the database's MDF file
15) Click the OK button to accept the database selection
16) Correct any invalid path in the database details: section of the lower half of the Attach Databases pane by

a) clicking on the appropriate '...' box associated with the 'Current File Path' column entry

b) navigating through the drives and folders in the Locate Database Files pop-up pane to find the appropriate file or folder

c) clicking on the appropriate file or folder to select it

d) clicking on the OK button to accept the change in location

17) After all appropriate changes have been made, click the OK button in the Attach Databases pane to complete the database attachment operation
18) After the database has been attached successfully, backup the database to ensure the Analytics files and folders have been restored to their online condition to allow the backup to succeed.

Solution 2:

1) Disable Analytics within the DA Case (if not already disabled)
2) If existing, delete any associated DataFullTextIndex folder(s)
3) Backup the DA database
4) Backup and truncate the DA database's transaction log using the built-in backup function of SQL Server (required to allow Analytics to be re-enabled)

For SQL Server 2005,

a. Open the Microsoft SQL Server Management Studio

b. Expand Databases in the left pane

c. Right click on the DA Customer database

d. Select the Tasks option

e. Select the 'Back Up...' option

f. In the 'Backup type:' field, click the drop down arrow

g. Select the Transaction Logs option

h. Provide the remaining required information

- Backup set name

- Backup set description (if desired)

- Backup set expiration information (if desired)

- Backup to information

i. Click the OK button to perform the backup

j. Click the OK button when the backup has completed

k. Close out of the Microsoft SQL Server Management Studio as needed

5) Enable Analytics within the DA Case

Note that the Analytics Rules are saved in the database, not in the 'DataFullTextIndex folder'.  When Analytics is enabled again for the Case, the accepted items in the Case will be reprocessed and the rules applied again.