Disaster Recovery

In Tamino, disaster recovery stands for the restoration of a Tamino database when everything is lost except for a backup of the database and recovery files. This may be the case after a total loss of the computing environment, in which backup and recovery files are still available on an archive. Unlike the normal restore and recover process, no information about the locations of the recovery files exists within the internal configuration store. Nevertheless, Tamino offers the possibility to recover from this disaster scenario if the following conditions are met:

The log spaces since the last backup used to create a database must be complete (no log space must be missing).
All log spaces must be accessible.
The log spaces must not have been used for a Recover until or Skip recover process before.

In order to meet these conditions, you should have a good archiving concept. Please contact Software AG Support, if you require support for this task.

The following two disaster recovery scenarios are described in this document:

Recovering from Internal Configuration Store Corruption
Recovering from the Loss of the Host Environment
Considerations for Incremental Backup
Using Backup Generations

Recovering from Internal Configuration Store Corruption

If the content of your internal configuration store (registry) is damaged for any reason (e.g. someone has accidentally deleted the information, or a disk error has occurred), you will not be able to access the Tamino databases. However, the file Registry.log keeps track of all internal configuration store entries that are relevant to Tamino and have occurred since the last installation of Tamino.

On Windows

Start of instruction set To recover from registry corruption

Use the import file provided by the installation of the latest Tamino version

regutil delete "HKLM\Software AG\Tamino"

regutil import "<DRIVE_LETTER>:\Documents and Settings\All Users\Application Data\Software AG\Tamino\Registry.export"
Apply the internal configuration store entries from the saved log with

regutil -f "<DRIVE_LETTER>:\Documents and Settings\All Users\Application Data\Software AG\Tamino \Registry.log"

On UNIX

Start of instruction set Case 1: A backup of $SAG/common/rgs/REGFILE is available

Restore the backup of the internal configuration store

$SAG/common/rgs/REGFILE
Apply the internal configuration store entries from the saved log with

regutil -f "$SAG/ino/Registry.log"

Start of instruction set Case 2: A backup of $SAG/common/rgs/REGFILE is not available

Save the file "$SAG/ino/Registry.log"
Reinstall Tamino, including the internal products.
Apply the internal configuration store entries from the saved log with

regutil -f <saved Registry.log>

Note:
Note that the backup file of the Registry.log must be a backup of the current Tamino installation, and not of a former version of Tamino.

Recovering from the Loss of the Host Environment

If you have lost your total computing environment due to a disaster, it is still possible to recover if a backup and all subsequent recovery files are available. However, the recovery files must not have been used for a restore with no full recover (recover with Skip Recover or Recover Until) process. The steps for disaster recovery in this case are:

Start of instruction set To recover from the loss of the host environment

In a new computing environment, install Tamino.
Perform a Create from Backup with the given backup file.

Note:
The backup file you specify must be a full backup file. You cannot use an incremental backup file to perform this step.

If no recovery files are to be applied or available, this is all that needs to be done. This may be the case if you are doing frequent backups.

If recovery files are available, apply them by following the next steps:

Add the internal configuration store entries for the recovery files.

To do so, create a script using the regutil utility to add the entries for the recovery files. An entry for a log space (with the extension .1LO) has the following structure:

HKEY_LOCAL_MACHINE
\SOFTWARE
 \Software AG
  \Tamino
   \servers
    \<database name>
     \savepoints
      \000000000000
       \log space
        \<session number>
         \<extent number>

The session number must be extended by leading zeroes as a 10 digit number, the extent number as a 5 digit number.

Here is an example: Two log spaces, AAF000010000000025.1L0 and AAF000010000000026.1L0 on the directory D:\archive, are to be processed.

create		"HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000\log space"

create	      "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000\log space\00025"

create	      "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000\log space\00025\00001"

setvaluedata "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000
              \log space\00025\00001" type "file"

setvaluedata "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000
              \log space\00025\00001" path "D:\archieve\AAF000010000000025.1L0"

create	      "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000
              \log space\00026"

create       "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000
              \log space\00026\00001"

setvaluedata "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000
              \log space\00026\00001" type "file"

setvaluedata "HKLMS\Software AG\Tamino\servers\db1\savepoints\000000000000
              \log space\00026\00001"  

path	        "D:\archieve\AAF000010000000026.1L0"

Other recovery files than log spaces (extension .1L0) only exists when the Tamino Data Loader was used without the concurrentWrite option. These are files with an extension of .1C0, .1C1 or .1C2. In case you want to do a disaster recovery with Tamino Data Loader recovery files, please contact Software AG Support to ask how to add registry entries.

Use the Restore/Recover function.

Note:
Note that the server must not be started between Create from Backup and performing the recover function.

Considerations for Incremental Backup

The incremental backup feature is selectable for each database individually, i.e. you can activate it for one database and deactivate it for another. When you use the Tamino Manager to activate or deactivate the feature for a particular database, the change takes effect the next time the database server is restarted.

To specify that a database can be used for making incremental backups, do the following:

Start of instruction set To specify that a database can be used for making incremental backups

In the Tamino Manager, select the node of the database.
Expand the tree of the node.
Expand the Properties node.
In the context menu of the Server node, select Modify.
Set the value of the property incremental backup to "yes" and choose OK.

The following restrictions apply for incremental backups:

Incremental backup is not available for external backup environments.
The parallel backup feature is not available for incremental backups.
Incremental backups are not available for read-only databases.

Using Backup Generations

Make sure to develop a backup strategy that gives you maximum protection for your data. If you have many update operations per day, it is recommended that you also back up the database at least daily. The number of backup generations to be retained can be defined using the backup parameter number of backup generations. If you maintain for example seven backup generations, you have one backup for each day of the week. When you create the 8th backup, the first one will be deleted.

Note:
Backup generations apply to full backups only, not to incremental backups.

Using the inoadmin tool the number of backup generations can be viewed via the getproperty command and modified via the setproperty command.

graphics/inoadmin_getproperty.png

The property that rules how many backups are kept is called number of backup generations. The default is five.

graphics/inoadmin_getproperty_mydb.png

The property can be modified via the setproperty command. Use the restart option to make the property change effective at once.

graphics/inoadmin_setproperty.png

The following sets the property to seven in order to have one backup for each day of the week.

graphics/inoadmin_setproperty_mydb.png

Refer also to the section Internal Backup and Restore in Tamino in the Backup Guide for more issues concerning backup generations.