ProxyHost with CVSnaptool - Truncating Exchange Logs

Overview

Batch Files for Exchange Log Truncation

• Example PreScan Batch File
• Example PostBackup Batch File

Configuring ProxyHost for Exchange Log Truncation

Considerations

Overview

The following section provides instructions for using CVSnaptool with a hardware snap engine and the ProxyHost iDataAgent to quiesce, unquiesce, and to eventually truncate the Exchange transaction logs. This is effected by first marking the last consistent log during the quiesce and saving that information to an ini file, which is referenced later to truncate the committed Exchange transaction logs from the quiesce time.

Batch Files for Exchange Log Truncation

A standard ProxyHost backup typically uses two batch files that perform the following functions:

• PreScan batch file
  • CVSnaptool quiesce
  • HW snap creation
  • CVSnaptool unquiesce
  • HW snap import
• PostBackup batch file
  • HW snap cleanup

With Exchange log truncation added, the batch file adds the Exchange Log truncation functionality:

• PreScan batch file
  • CVSnaptool quiesce and mark last consistent log in ini file
  • HW snap creation
  • CVSnaptool unquiesce
  • HW snap import
• PostBackup batch file
  • HW snap cleanup
  • CVSnaptool Exchange log truncation based on ini file

Example PreScan Batch File

@REM Vars (var for ini file is mandatory, call it whatever you want)

SET CV_INI_FILE_NAME=%windir%\temp\Truncate.ini

SET GalaxyBaseDir=<install_direcory>\Base

@REM Cleanup preexisting ini file first (NEW - a safety measure to guarantee no leftover exchange info).

DEL %CV_INI_FILE_NAME%

@REM Quiesce section (Changes).

"%GalaxyBaseDir%"\Cvsnaptool.exe -x <client_name> -a ex2003 -g SG2 -o quiesce -markexchlogs -ini %CV_INI_FILE_NAME% -vm <InstanceName*> -cn <ClientName>

@REM Snap section (no change)

<HW snap creation cmd>

@REM Unquiesce section (no change)

"%GalaxyBaseDir%"\Cvsnaptool.exe -x <client_name> -a ex2003 -g SG2 -o unquiesce -vm <InstanceName*> -cn <ClientName> 

@REM Import section (no change)

<HW snap import cmd>

Example PostBackup Batch File

@REM Vars (changes)

IF '%6'=='1' GOTO BACKUP_SUCCESSFUL

net send <client_name> backup phase did not complete successfully, so I won't execute the log truncation

exit 1

:BACKUP_SUCCESSFUL

SET CV_INI_FILE_NAME=%windir%\temp\Truncate.ini SET GalaxyBaseDir=<install_direcory>\Base

@REM Destroy snap

net send <client_name> snap destroyed

@REM Truncate section (NEW).

"%GalaxyBaseDir%"\Cvsnaptool.exe -o truncateexchlogs -ini %CV_INI_FILE_NAME% -vm <InstanceName*> -cn <ClientName>

* InstanceName is the name used for a Proxy Host instance (by default it is Instance001). If multiple instances of Proxy Host are installed use the corresponding instance name, see Multi Instancing for more information.

Configuring ProxyHost for Exchange Log Truncation

Required Capability: Capabilities and Permitted Actions

To configure ProxyHost to truncate Exchange Logs:

1. Create the PreScan and PostBackup batch files, using the example scripts above. These files must reside on the backup host or primary host.
2. Install the ProxyHost iDataAgent on the production server, and the Windows File System iDataAgent on both the production server and backup host. Refer to Deployment - ProxyHost iDataAgent and Deployment - Windows File System iDataAgent.
3. Configure a supported Snapshots Environment.
4. Create a New Subclient, and configure subclient content. Click the Pre/Post Process tab of the Subclient Properties dialog box. In the PreScan field, type the path to the batch file file that contains those commands that are to run before each backup of the subclient, or click Browse to locate and select the batch file. Do the same for the PostBackup field.
5. Perform a backup. For more information, see Backup - ProxyHost.

Additional Suggestions:

• View the CVSnaptool log file during the quiesce –markexchlogs command to see what is marked as the 'last consistent log'. Everything up to, but not including, that log will be truncated on that Exchange storage group.
• Open the ini file after the quiesce command has run to verify it contains accurate information on the Exchange storage group you are quiescing, including the log prefix and last consistent log.
• View the CVSnaptool log file again during the truncateexchlogs command to see which logs will be deleted, and on which Exchange storage groups.

Considerations

• The ini file must have same path and name in all scripts that reference it, although the variable name can be different.
• On a cluster, the ini file must be on a shared disk resource, so that in the event of a failover, the file can still be accessed by the script.
• The cvsnaptool –truncate command is sensitive; certain normal cvsnaptool arguments are not necessary and may cause the Exchange log truncation to fail. A server name (–x) is not required, as it is stored in the ini file, nor is app name (–a) since Exchange is assumed.
• If you omit the –g switch from the CVSnaptool quiesce command, it will quiesce all of the storage groups on your server. If you omit the –g switch from the cvsnaptool truncate command, it will truncate all of the storage groups on your server. You can use –g to truncate a specific storage group, but if you originally used –g in the quiesce/mark, then only that storage group will actually be listed in the ini file so it is not necessary. However, if you quiesced all storage groups originally, you can use –g in the truncate command to only truncate one of them.
• For a storage group with spaces in the name, e.g., FIRST STORAGE GROUP, use double quotes around the name when using the –g switch.
• When using multiple ProxyHost subclients for your Exchange storage groups, the ini files for each group must have unique names; using the same ini file name for multiple subclients creates a risk of them getting overwritten or populated with the wrong info.
• While a single storage group can be quiesced with the –g switch, and all storage groups can be quiesced by omitting the –g switch, there is no way to specify only some storage groups, for instance only two out of three. To accomplish this, repeat the quiesce command with the –g switch for each storage group, but remember to use a different ini file for each of these commands; otherwise, the latter storage group data will overwrite the data from the previous storage group.
• PostBackup scripts are executed without regard to the success or failure of the backup attempt itself. However, the PostBackup script contains the log truncation step and it is very important that log truncation be executed only after a successful backup. This is ensured by utilizing a status variable, passed by the Job Manager to the PostBackup phase, in the 'if' statement in the example script to determine whether log truncation should run or not.