Q: Does CSBS support backup of all EVSs in the ECS?

A: Supported. CSBS can back up and restore all the EVS disks in an ECS as a whole by creating a backup policy and binding such backup policy to the ECS, but you cannot back up part of the EVSs in an ECS.

Q: Is it necessary to shut down the ECS when performing CSBS?

A: There is no need to do so. CSBS supports the backup of ECS that is running. When the ECS is running normally, in addition to writing data to the EVS, some of the latest data is stored in the memory as cache data. During the backup, the caching data in the memory will not be automatically written to the EVS, which may otherwise lead to application inconsistency.

Therefore, in order to ensure the integrity of the backup data to the maximum extent, it is better to execute the CSBS in the early morning when no data is written to the EVS, or suspend all data writing operations and stop the application system before executing the CSBS. If there is extremely high requirements for the integrity of the backup data, shut down the ECS (to write the cached data to the EVS) and perform offline CSBS.

Q: How long does it take to back up an ECS?

A: The CSBS executes full backup for the first time and incremental backup subsequently. Therefore, it will take alonger time for the first backup and a shorter time for subsequent backups. For example: To back up an ECS with 100GB of existing data, the first full backup takes about 30 minutes; assuming that 15GB of data is newly generated or changed before the next backup, the incremental backup takes about 8 minutes.

Q: Does CSBS support cross-region backup for ECSs?

A: Currently it only supports the backup and recovery within a region rather than across regions.

Q: Can I use the backup of a former ECS to recover the data to a new ECS?

A: If your ECS has been backed up and changed (adding or expanding EVSs), you can still use the original backup to restore data. However, due to the limitation of the file system, the EVS is restored to its original state after data recovery. You are advised to back up data after the change.

Q: How do I handle CSBS exceptions?

A: The current exceptions are mainly due to the abnormal status of the ECS backup. When encountering such exceptions, please refer to the following suggestions for repair.

Exceptions	Suggestions
Error	You can delete the ECS backup in an error status and then create it again.
Failed to delete	Please contact the Customer Service for help. The Customer Service will actively help you resolve this issue. Before that, it is recommended not to perform any other operations on the backup data. If you need quick response of the Customer Service, please contact them at the first time.

Q: Can CSBS back up an ECS that is mounted with shared disks?

A: You can back up an ECS that is mounted with shared disks.

Q: Can ECS containing application systems be backed up?

A: Yes. For applications that have consistency requirements such as databases or email systems, it is recommended to suspend the writing of all data before backup. If the writing operation cannot be suspended, you can stop the application system or the ECS to execute the offline backup. If none is performed before the backup, the ECS will be recovered to a status as if it is restarted after an abnormal power outage, for which the database will execute a log rollback to ensure consistency.

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