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2.2. Backup drivers

This section describes how to configure the cinder-backup service and its drivers.
To set a backup driver, use the backup_driver flag. By default there is no backup driver enabled.

2.2.1. Ceph backup driver

The Ceph backup driver backs up volumes of any type to a Ceph back-end store. The driver can also detect whether the volume to be backed up is a Ceph RBD volume, and if so, it tries to perform incremental and differential backups.
For source Ceph RBD volumes, you can perform backups within the same Ceph pool (not recommended). You can also perform backups between different Ceph pools and between different Ceph clusters.
At the time of writing, differential backup support in Ceph/librbd was quite new. This driver attempts a differential backup in the first instance. If the differential backup fails, the driver falls back to full backup/copy.
If incremental backups are used, multiple backups of the same volume are stored as snapshots so that minimal space is consumed in the backup store. It takes far less time to restore a volume than to take a full copy.
Note
Block Storage enables you to:
  • Restore to a new volume, which is the default and recommended action.
  • Restore to the original volume from which the backup was taken. The restore action takes a full copy because this is the safest action.
To enable the Ceph backup driver, include the following option in the cinder.conf file: 
backup_driver = cinder.backup.drivers.ceph
The following configuration options are available for the Ceph backup driver.

Table 2.22. Description of Ceph backup driver configuration options

Configuration option = Default value Description
[DEFAULT]
backup_ceph_chunk_size = 134217728 (IntOpt) The chunk size, in bytes, that a backup is broken into before transfer to the Ceph object store.
backup_ceph_conf = /etc/ceph/ceph.conf (StrOpt) Ceph configuration file to use.
backup_ceph_pool = backups (StrOpt) The Ceph pool where volume backups are stored.
backup_ceph_stripe_count = 0 (IntOpt) RBD stripe count to use when creating a backup image.
backup_ceph_stripe_unit = 0 (IntOpt) RBD stripe unit to use when creating a backup image.
backup_ceph_user = cinder (StrOpt) The Ceph user to connect with. Default here is to use the same user as for Cinder volumes. If not using cephx this should be set to None.
restore_discard_excess_bytes = True (BoolOpt) If True, always discard excess bytes when restoring volumes i.e. pad with zeroes.
This example shows the default options for the Ceph backup driver. 
backup_ceph_conf=/etc/ceph/ceph.conf
backup_ceph_user = cinder
backup_ceph_chunk_size = 134217728
backup_ceph_pool = backups
backup_ceph_stripe_unit = 0
backup_ceph_stripe_count = 0

2.2.2. IBM Tivoli Storage Manager backup driver

The IBM Tivoli Storage Manager (TSM) backup driver enables performing volume backups to a TSM server.
The TSM client should be installed and configured on the machine running the cinder-backup service. See the IBM Tivoli Storage Manager Backup-Archive Client Installation and User's Guide for details on installing the TSM client.
To enable the IBM TSM backup driver, include the following option in cinder.conf: 
backup_driver = cinder.backup.drivers.tsm
The following configuration options are available for the TSM backup driver.

Table 2.23. Description of IBM Tivoli Storage Manager backup driver configuration options

Configuration option = Default value Description
[DEFAULT]
backup_tsm_compression = True (BoolOpt) Enable or Disable compression for backups
backup_tsm_password = password (StrOpt) TSM password for the running username
backup_tsm_volume_prefix = backup (StrOpt) Volume prefix for the backup id when backing up to TSM
This example shows the default options for the TSM backup driver. 
backup_tsm_volume_prefix = backup
backup_tsm_password = password
backup_tsm_compression = True

2.2.3. Swift backup driver

The backup driver for the swift back end performs a volume backup to an object storage system.
To enable the swift backup driver, include the following option in the cinder.conf file: 
backup_driver = cinder.backup.drivers.swift
The following configuration options are available for the Swift back-end backup driver.

Table 2.24. Description of Swift backup driver configuration options

Configuration option = Default value Description
[DEFAULT]
backup_swift_auth = per_user (StrOpt) Swift authentication mechanism
backup_swift_auth_version = 1 (StrOpt) Swift authentication version. Specify "1" for auth 1.0, or "2" for auth 2.0
backup_swift_block_size = 32768 (IntOpt) The size in bytes that changes are tracked for incremental backups. backup_swift_object_size has to be multiple of backup_swift_block_size.
backup_swift_ca_cert_file = None (StrOpt) Location of the CA certificate file to use for swift client requests.
backup_swift_container = volumebackups (StrOpt) The default Swift container to use
backup_swift_enable_progress_timer = True (BoolOpt) Enable or Disable the timer to send the periodic progress notifications to Ceilometer when backing up the volume to the Swift backend storage. The default value is True to enable the timer.
backup_swift_key = None (StrOpt) Swift key for authentication
backup_swift_object_size = 52428800 (IntOpt) The size in bytes of Swift backup objects
backup_swift_retry_attempts = 3 (IntOpt) The number of retries to make for Swift operations
backup_swift_retry_backoff = 2 (IntOpt) The backoff time in seconds between Swift retries
backup_swift_tenant = None (StrOpt) Swift tenant/account name. Required when connecting to an auth 2.0 system
backup_swift_url = None (StrOpt) The URL of the Swift endpoint
backup_swift_user = None (StrOpt) Swift user name
swift_catalog_info = object-store:swift:publicURL (StrOpt) Info to match when looking for swift in the service catalog. Format is: separated values of the form: <service_type>:<service_name>:<endpoint_type> - Only used if backup_swift_url is unset
To enable the swift backup driver for 1.0 or 2.0 authentication version, specify 1 or 2 correspondingly. For example: 
backup_swift_auth_version = 2
In addition, the 2.0 authentication system requires backup_swift_tenant setting: 
backup_swift_tenant = <None>
This example shows the default options for the Swift back-end backup driver. 
backup_swift_url = http://localhost:8080/v1/AUTH_
backup_swift_auth = per_user
backup_swift_auth_version = 1
backup_swift_user = <None>
backup_swift_key = <None>
backup_swift_container = volumebackups
backup_swift_object_size = 52428800
backup_swift_retry_attempts = 3
backup_swift_retry_backoff = 2
backup_compression_algorithm = zlib

2.2.4. NFS backup driver

The backup driver for the NFS back end backs up volumes of any type to an NFS exported backup repository.
To enable the NFS backup driver, include the following option in the [DEFAULT] section of the cinder.conf file: 
backup_driver = cinder.backup.drivers.nfs
The following configuration options are available for the NFS back-end backup driver.

Table 2.25. Description of NFS backup driver configuration options

Configuration option = Default value Description
[DEFAULT]
backup_container = None (StrOpt) Custom directory to use for backups.
backup_enable_progress_timer = True (BoolOpt) Enable or Disable the timer to send the periodic progress notifications to Ceilometer when backing up the volume to the backend storage. The default value is True to enable the timer.
backup_file_size = 1999994880 (IntOpt) The maximum size in bytes of the files used to hold backups. If the volume being backed up exceeds this size, then it will be backed up into multiple files.backup_file_size must be a multiple of backup_sha_block_size_bytes.
backup_mount_options = None (StrOpt) Mount options passed to the NFS client. See NFS man page for details.
backup_mount_point_base = $state_path/backup_mount (StrOpt) Base dir containing mount point for NFS share.
backup_sha_block_size_bytes = 32768 (IntOpt) The size in bytes that changes are tracked for incremental backups. backup_file_size has to be multiple of backup_sha_block_size_bytes.
backup_share = None (StrOpt) NFS share in hostname:path, ipv4addr:path, or "[ipv6addr]:path" format.