Backup servers are servers responsible for storing backups and templates of virtual servers running in the cloud, in order to prevent data loss in the event of failure.
There are now three ways to handle backup and template storage in your cloud:
Only one Backup Scheme can be used per cloud.
Basic Backup Scheme
Running disk-related actions on Compute resources
This was the default backup method prior to OnApp Cloud 2.3.2. In this scenario, template/backup storage works as follows:
- Backups and templates are stored on a single backup/template server.
- Backup transactions are performed on Compute resources.
- After the backup is taken on a Compute resource, it is put on the backup/template server. This server can be accessed via SSH or NFS.
- In order to make this server accessible via SSH, you should configure SSH file transfer server options.
In order to make this server accessible via NFS, you should mount the appropriate directory from this server to each Compute resource.
Centos now defaults to NFSv4. This is known to cause compatibility issues so we strongly recommend that you use NFSv3 for all mounts. This can be done by passing -t nfs -o vers=3 in any mount commands.
- Backups created are stored at the path defined in Admin > Settings > Configuration > Backups/templates
Advanced Backup Scheme
Running disk-related actions on one or more dedicated backup servers
This backup scheme can be used in OnApp Cloud 2.3.2 and above. This option does not use Compute resources to take backups. Instead, you deploy one or more dedicated backup servers, which handle transactions and store all backups & templates.
- If you have added one or more backup servers, all backups will be stored on these servers.
- If there is more than one backup server, backups are performed on the server with the most available disk space.
- A network is used to connect Compute resource with the backup server. (An IP address is assigned to Compute resource and a backup server to build an iSCSI connection. If no IP is assigned to the Compute resource, an IP from the management network will be used.
- Using this method, templates are also stored on the dedicated backup server(s). When converting a backup to a template, the new template will be stored on the same server as the backup.
Dedicated backup servers handle the following activities:
Backup and template related actions
- Take a backup
- Restore a backup
- Convert backup to template
- Destroy backup
- Destroy template
Disk related actions
- Configure OS on virtual server
- Provision virtual server
- Create disk
- Format disk
- Resize disk
- Migrate disk
- Destroy disk
VS related actions
- Set SSH keys
- Network Configuration
- Rebuild network
- Attach/detach Network Interface
If there are no dedicated backup servers in the cloud, all these actions will be performed by Compute resources, and backups/templates stored according to the settings defined in Admin > Settings > Configuration > Backups/templates.
- The use of dedicated backup servers is available for non-local data stores only.
- Volume groups of each data store based on SAN must be shared with the backup server.
- If your cloud uses a combination of local storage and SANs, you will only be able to use the new backup method for virtual servers that have been allocated SAN-based storage.
- If only local storage is used, you shouldn't define any dedicated backup servers – instead, configure your SSH or NFS settings in the Admin > Settings > Configuration > Backups/templates menu.
CloudBoot Backup Scheme
Starting from the OnApp v3.0 you can use dedicated CloudBoot backup servers in your cloud. Please refer to the Create CloudBoot Backup Server section for more details.
Disabling backup servers
Be aware, that if you switch off a backup server, transactions "restore backups" (those backups which are located on this server) will be failed. Also if OS template is located ONLY on this backup server, provisioning disk transaction will be failed.