Appendix B. Advanced Block Storage backup configuration options

Before director-deployed installations, the cinder.conf file configured the Block Storage service and the backup service. When a value from cinder.conf does not have an orchestration (heat) template equivalent, you can use a custom environment file to pass values to the director. Add the values to an ExtraConfig section in the parameter_defaults section of a custom environment file, for example, the cinder-backup-settings.yaml file.

With ExtraConfig, you can add additional hiera configuration to inject into the cluster on all nodes. These settings are included on a dedicated backup node. However, if you used ControllerExtraConfig instead of ExtraConfig, your settings are installed on Controller nodes and not on a dedicated backup node.

You can substitute DEFAULT/[cinder.conf setting]` for the setting from the DEFAULT section of the cinder.conf file. The following example shows how the ExtraConfig entries appear in a YAML file:

parameter_defaults:
 ExtraConfig:
   cinder::config::cinder_config:
     DEFAULT/backup_compression_algorithm:
       value: None

Table B.1 lists backup-related sample options.

Table B.1. Block Storage backup service configuration options

OptionTypeDefault valueDescription

backup_service_inithost_offload

Optional

True

Offload pending backup delete during backup service startup. If false, the backup service remains down until all pending backups are deleted.

use_multipath_for_image_xfer

Optional

False

Attach volumes using multipath, if available, during backup and restore procedures. This affects all cinder attach operations, such as create volume from image, generic cold migrations, and other operations.

num_volume_device_scan_tries

Optional

3

The maximum number of times to rescan targets to find volumes during attach.

backup_workers

Optional

1

Number of backup processes to run. Running multiple concurrent backups or restores with compression results in significant performance gains.

backup_native_threads_pool_size

Optional

60

Size of the native threads pool for the backups. Most backup drivers rely heavily on this. You can decrease the value for specific drivers that do not rely on this option.

backup_share

Required

 

Set to HOST:_EXPORT_PATH_.

backup_container

Optional

None

(String) Custom directory to use for backups.

backup_enable_progress_timer

Optional

True

Enable (true) or disable (false) the timer to send the periodic progress notifications to the Telemetry service (ceilometer) when backing up the volume to the backend storage.

backup_mount_options

Optional

 

Comma-separated list of options that you can specify when you mount the NFS export that is specified in backup_share.

backup_mount_point_base

Optional

$state_path/backup_mount

(String) Base directory that contains mount point for NFS share.

backup_compression_algorithm

Optional

zlib

The compression algorithm that you want to use when you send backup data to the repository. Valid values are zlib, bz2, and None.

backup_file_size

Optional

1999994880

Data from cinder volumes that are larger than this value are stored as multiple files in the backup repository. This option must be a multiple of backup_sha_block_size_bytes.

backup_sha_block_size_bytes

Optional

32768

Size of cinder volume blocks for digital signature calculation