14 Backup and Restore

The most comprehensive method for backing up your Uyuni installation is to back up the relevant files and directories. This can save you time in administering your backup, and can be faster to reinstall and re-synchronize in the case of failure. However, this method requires significant disk space and could take a long time to perform the backup.

If you want to only back up the required files and directories, use this list:

Note

To make this process simpler, and more comprehensive, we recommend backing up the entire /etc and /root directories, not just the ones specified here.

Important

You will also need to back up your database, which you can do by copying /var/spacewalk/db-backup or by using the smdba tool, which is explained later in this chapter.

The smdba tool is used for managing a local PostgreSQL database. It allows you to back up and restore your database, and manage backups. It can also be used to check the status of your database, and perform administration tasks, such as restarting.

Note

The smdba tool works with local PostgreSQL databases only, it will not work with remotely accessed databases, or Oracle databases.

Important

The smdba tool requires sudo access, in order to execute system changes. Ensure you have enabled sudo access for the admin user before you begin, by checking the /etc/sudoers file for this line:

admin   ALL=(postgres) /usr/bin/smdba

Check the runtime status of your database with the smdba db-status command. This command will return either online or offline:

smdba db-status
Checking database core...       online

To check the full connection to the database, use the smdba db-check command. Depending on your environment, this command will report on the status of listeners, in addition to connectivity status.

smdba db-check

Starting and stopping the database can be performed with smdba db-start and smdba db-stop

smdba db-start
Starting core...       done

smdba db-stop
Stopping the SUSE Manager database...
Stopping core:         done

The smdba tool performs a continuous archiving backup. This backup method combines a log of every change made to the database during the current session, with a series of more traditional backup files. When a crash occurs, the database state is first restored from the most recent backup file on disk, then the log of the current session is replayed exactly, to bring the database back to a current state. A continuous archiving backup with smdba is performed with the database running, so there is no need for downtime.

This method of backing up is stable and generally creates consistent snapshots, however it can take up a lot of storage space. Ensure you have at least three times the current database size of space available for backups. You can check your current database size by navigating to /var/lib/pgsql/ and running df -h.

The smdba tool also manages your archives, keeping only the most recent backup, and the current archive of logs. The log files can only be a maximum file size of 16 MB, so a new log file will be created once the files reach this size. Every time you create a new backup, previous backups will be purged to release disk space. We recommend you use cron to schedule your smdba backups to ensure that your storage is managed effectively, and you always have a backup ready in case of failure.

14.3.1 Performing a Manual Database Backup #

The smdba tool can be run directly from the command line. We recommend you run a manual database backup immediately after installation, or if you have made any significant changes to your configuration.

Note

When smdba is run for the first time, or if you have changed the location of the backup, it will need to restart your database before performing the archive. This will result in a small amount of downtime. Note that regular database backups will not require any downtime.

Procedure: Performing a Manual Database Backup #

1. Allocate permanent storage space for your backup. In this procedure, we will be using an NFS share located at /var/spacewalk/. This will become a permanent target for your backup, so ensure it will remain accessible by your server at all times.

2. In your backup location, create a directory for the backup:

   sudo -u postgres mkdir /var/spacewalk/db-backup

   Or, as root:

   install -d -o postgres /var/spacewalk/db-backup

3. Ensure you have the correct permissions set on the backup location:

   chown postgres:postgres /var/spacewalk/db-backup

4. To run a backup for the first time, run the smdba backup-hot command with the enable option set. This will create the backup in the specified directory, and, if necessary, restart the database:

   smdba backup-hot --enable=on --backup-dir=/var/spacewalk/db-backup

5. Check that the backup files exist in the /mnt/backup/database directory, to ensure that your backup has been successful.

14.3.2 Scheduling Automatic Backups #

You do not need to shut down your system in order to perform a database backup with smdba. However, because it is a large operation, database performance can slow down while the backup is running. We recommend you schedule regular database backups for a low-traffic period, to minimize disruption.

Important

Ensure you have at least three times the current database size of space available for backups. You can check your current database size by navigating to /var/lib/pgsql/ and running df -h.

Procedure: Scheduling Automatic Backups #

1. Create a directory for the backup, and set the appropriate permissions:

   # mkdir /var/spacewalk/db-backup
   # chown -R postgres:postgres /var/spacewalk/db-backup
   # chmod 700 /var/spacewalk/db-backup

2. Open /etc/cron.d/db-backup-mgr, or create it if it doesn’t exist, and add the following line to create the cron job:

   0 2 * * * root /usr/bin/smdba backup-hot --enable=on --backup-dir=/var/spacewalk/db-backup

3. Check the backup directory regularly to ensure the backups are working as expected.

The smdba tool can be used to restore from backup in the case of failure.

spacewalk-data-fsck

In SUSE Manager with an embedded database, archive logging is enabled by default. This feature allows the database management tool smdba to perform hot backups.

With archive log enabled, even more data is stored on the hard disk:

Creating a user and syncing the channels:

Postgresql will generate an additional ~1 GB of data. So it is important to think about a backup strategy and create a backups in a regular way.

Archive logs are stored at:

Database administrators may use the subcommand space-overview to get a report about occupied table spaces, for example:

smdba space-overview
SUSE Manager Database Control. Version 1.5.2
Copyright (c) 2012 by SUSE Linux Products GmbH


Tablespace  | Size (Mb) | Avail (Mb) | Use %
------------+-----------+------------+------
postgres    | 7         | 49168      | 0.013
susemanager | 776       | 48399      | 1.602

The following command is available for Postgresql. For a more detailed report, use the space-tables subcommand. It lists the table and its size, for example:

smdba space-tables
SUSE Manager Database Control. Version 1.5.2
Copyright (c) 2012 by SUSE Linux Products GmbH


Table                                 | Size
--------------------------------------+-----------
public.all_primary_keys               | 0 bytes
public.all_tab_columns                | 0 bytes
public.allserverkeywordsincereboot    | 0 bytes
public.dblink_pkey_results            | 0 bytes
public.dual                           | 8192 bytes
public.evr_t                          | 0 bytes
public.log                            | 32 kB
...

It is possible to move the database to another location. For example if your database storage space is running low. The following procedure will guide you through moving the database to a new location for use by SUSE Manager.

This section provides guidance on restoring your server after its root partition has crashed. This section assumes you have setup your server similar to the procedure explained in Getting Started guide with separate partitions for the database and for channels mounted at /var/lib/pgsql and /var/spacewalk/ .

The information for connecting to the SUSE Manager database is located in /etc/rhn/rhn.conf :

db_backend = postgresql
db_user = susemanager
db_password = susemanager
db_name = susemanager
db_host = localhost
db_port = 5432
db_ssl_enabled =