- describe db backup and restore

DisasterManagement.md

@@ -157,3 +157,57 @@ worstcase: Restore whole data disk, which is mounted into /storage, and all of i
 
 One of the common backup and restore configurations is an environment with two SQL Servers (SQLServer-1 and SQLServer-2), two SQL Server instances (SQLInstance-1 and SQLInstance-2), and one database named SQLDB-1 which will be backed up, transferred, and restored to SQLServer-2.
 ![Image](./db_backup.drawio.svg)
+<br>
+<br>
+## Create DB backup
+
+To create a backup of a research database using pg_dump, you can follow these steps:
+
+1. Open a terminal or command prompt and navigate to the directory where you want to store the backup file.
+2. Type the following command to create a backup of the database:
+
+   ```bash
+   pg_dump -U <username> -E UTF8 -F c -b -v -f <backup_file_name>.backup <database_name>
+   ```
+
+   Here, replace **username** with the username of the database, **backup_file_name** with the name you want to give to the backup file, and **database_name** with the name of the research database you want to backup.
+
+   -E is for the encoding, e.g. UTF8
+   -F c specifies the format of the backup as a custom format, which is more flexible than plain SQL text format. \
+   -b includes the backup of the objects such as functions and procedures. \
+   -v enables verbose mode which will display the progress of the backup process. \
+
+   Usually the timestamp is integrated into the backup_file_name:
+
+   ```bash
+   pg_dump -U <username> -F c -b -v -f <database_name>_$(date +"%Y%m%d_%H%M%S").backup <database_name>
+   e.g.:
+   pg_dump -U tethys_user -E UTF8 -F c -b -v -f /home/user/backups/tethys_$(date +"%Y%m%d").backup tethys
+   ```
+
+3. When you run the command, you will be prompted to enter the password for the database user. Enter the password and press enter.
+4. The pg_dump command will start creating the backup file. Wait until it completes, which may take several minutes depending on the size of the database.
+
+5. Once the backup is complete, you will see a message indicating that the backup has been created successfully.
+
+It's important to note that the backup file may contain sensitive information, so it should be stored securely and only accessible to authorized personnel.
+<br>
+<br>
+## Restore DB on second DB-Server
+
+To restore a backup of the research database using pg_restore, you can follow these steps:
+
+1.  Open a terminal or command prompt and navigate to the directory where the backup file is located.
+2.  Type the following command to restore the backup to the database:
+    ```bash
+    pg_restore -U <username> -d <database_name> <backup_file_name>
+    ```
+    Here, replace <username> with the username of the database, <database_name> with the name of the research database you want to restore the backup to, and <backup_file_name> with the name of the backup file.
+3.  When you run the command, you will be prompted to enter the password for the database user. Enter the password and press enter.
+4.  The pg_restore command will start restoring the backup file to the database. Wait until it completes, which may take several minutes depending on the size of the database.
+
+e.g.
+```
+pg_restore -h localhost -p 5432 -U tethys_user -d tethys_db -v /tmp/tethys_20230404.backup
+```
+Once the restore process is complete, the research database should be fully recovered with all its data and objects.