Recovering the master Database

A damaged master database can be caused by a media failure in the area on which master is stored, or by internal corruption in the database.

Your master database is damaged if:

SAP ASE cannot start.
There are frequent or debilitating segmentation faults or input/output errors.
dbcc reports damage during a regular check of your databases.

This section describes how to recover the master database and to rebuild the master device. It assumes:

The master database is corrupt, or the master device is damaged.
You have up-to-date printouts of the system tables, listed in System Administration Guide: Volume 1 > System and Optional Databases.
The master device contains only the master database, tempdb, model, and sybsystemdb.
You have an up-to-date backup of the master database, and you have not initialized any devices or created or altered any databases since last dumping master.
Your server uses the default sort order.

The Error Message and Troubleshooting Guide provides more complete coverage of recovery scenarios.

Recovery Procedure
To restore a damaged master device, follow the recovery steps below, or use the sybrestore utility.
Finding Copies of System Tables
Find copies of the system tables that you have saved to a file: sysdatabases, sysdevices, sysusages, sysloginroles, and syslogins.
Building a New Master Device
Build a new master device only if your old master device is damaged beyond repair. Otherwise, you can re-create the master and model databases on your existing master device.
Starting SAP ASE in Master-Recover Mode
Start SAP ASE in master-recover mode with the dataserver -m (UNIX and Windows) option.
Re-creating Device Allocations for master
If you re-created your master device according to the process described in Rebuilding a New Master Device, your master database may be too small.
Checking Your Backup Server sysservers Information
You must verify that sysservers includes the correct information.
Verifying That Your Backup Server Is Running
On UNIX platforms, use the showserver command to verify that Backup Server is running; restart the server if necessary.
Loading a Backup of master
Load the most recent backup of the master database.
Updating the number of devices Configuration Parameter
You must update the number of devices configuration parameter if you use more than the default number of database devices.
Restarting SAP ASE in Master-Recover Mode
Use startserver to restart SAP ASE in master-recover mode.
Checking System Tables to Verify Current Backup of master
If you have backed up the master database since issuing the most recent disk init, create database, or alter database command, then the contents of sysusages, sysdatabases, and sysdevices match your hard copy.
Restarting SAP ASE
Restart SAP ASE in normal (multiuser) mode.
Restoring Server User IDs
Check your hard copy of syslogins and your restored syslogins table.
Restoring the model Database
Restore the model database.
Checking SAP ASE
Compare your hard copy versions of system tables with the versions of the system tables you brought online in the restored databases.
Backing Up master
When you have completely restored the master database and have run full dbcc integrity checks, back up the database using your usual dump commands.

Parent topic: Restoring the System Databases