Changing the redundancy scheme for backup storage
You can update the redundancy scheme used for backup storage by changing the storage policy. Such a configurable redundancy scheme ensures high scalability and maximum efficiency of backup storage.
During the re-encoding process, data is partially stored with a new redundancy scheme, and the other part is stored with an old scheme. However, the system uses the storage policy with the least redundancy. For example, if you are switching from the 1+0 encoding mode to 1+2, the system will use the 1+0 encoding mode. In this case, it is critical not to turn off any storage node or disk until the process is complete.
Limitations
- Redundancy by replication is not supported for backup storage.
Prerequisites
- A clear understanding of the concept Storage policies.
- The backup storage cluster is created and registered in the Cloud Management Panel, as described in Provisioning backup storage space.
To change the storage policy
Admin panel
- On the Storage services > Backup storage screen, go to the Settings tab, and then click Storage policy.
-
Select the desired storage tier, failure domain, or data redundancy mode.
- Click Save.
When the re-encoding process starts, its progress and the estimated time of completion will be shown on the screen. During this process, you can select another redundancy scheme. In this case, the current re-encoding process will be stopped and the new redundancy scheme will be applied.
Command-line interface
Use the following command:
vinfra service backup volume-params change [--tier {0,1,2,3}] [--encoding <M>+<N>] [--failure-domain {disk,host,rack,row,room}]
--tier {0,1,2,3}
- Storage tier
--encoding <M>+<N>
-
Storage erasure encoding mapping in the format:
M
: the number of data blocksN
: the number of parity blocks
--failure-domain {0,1,2,3,4}
- Storage failure domain
For example, to change the storage tier to 0, the erasure coding scheme to 1+2, and the failure domain to host, run:
# vinfra service backup volume-params change --tier 0 --encoding 1+2 \ --failure-domain host
The updated parameters will be shown in the vinfra service backup volume-params show
output:
# vinfra service backup volume-params show +----------------+-------------+ | Field | Value | +----------------+-------------+ | failure_domain | host | | redundancy | m: 1 | | | n: 2 | | | type: raid6 | | tier | 0 | +----------------+-------------+