What is Volume Backup Service?

Volume Backup Service (VBS, VBS) is a backup service provided for the system disk and data disk of the cloud server. VBS allows you to back up your Elastic Volume Service (EVS) that stores important data, and restore your data from backups against EVS faults, accidental deletion of data, and hacker attacks, thus maximizing the security of your data.

Generally, VBS is divided into full backup and incremental backup. By default, the initial backup is a full backup, and subsequent backups are incremental backups.

What are full and incremental backups?

Generally, VBS supports both full backups and incremental backups.

Full backup: Backs up all the data of the entire EVS disk at a certain time. Regardless of whether the data changes or not, a new backup copy will be created. By default, the system performs a full backup initially. For example: when the capacity of an EVS is 50 GB and 10 GB of data has been written, 10 GB of data will be backed up in the EVS.
Incremental backup: Only backs up data changed since the last backup. After the initial backup, the subsequent backups are all incremental backups by default. For example: when the capacity of an EVS is 50 GB and 10 GB of data has been written and backed up initially, if 5 GB of data is subsequently written or changed, only the added or changed 5 GB of data will be backed up.

VBS allows you to restore full data using either a full backup or incremental backup. Deleting any backup will not affect the data restoration function of other backups.

What are the connections and differences between EVS Backup and EVS Snapshot?

Both EVS Snapshot and EVS Backup are important means of data protection and restoration, which differ in their functions and uses. Details are described in the table below:

Difference	EVS Snapshot	EVS Backup
Storage location	Snapshots and original data on the EVS are stored in the same cloud storage cluster.	Backups and original data on the EVS are not stored in the same cloud storage cluster but in the ZOS as backup files. Data can still be restored even if the EVS is damaged.
Data synchronization	Save the EVS data at the specified time. You can set an automatic snapshot policy. If the EVS that created the snapshot is deleted, the corresponding snapshot will also be deleted or needs to be deleted manually by users. After you reinstall or change your operating system, the snapshots of the system disks and data disks will not be deleted, and the snapshots of the data disks can be used as usual. Retaining the snapshots of a single disk on the system disks may cause the host re-installation or operating system change failure. Therefore, we recommend that you manuallydelete snapshotsbefore such re-installation or change operation.	Save the EVS data at a specified time. You can set up automatic backup. If the EVS that created the backup is deleted, the corresponding backup will not be deleted but will be stored independently in the object storage.
Service recovery	Restore the EVS data through snapshot rollback, or use a snapshot as the data source to create an EVS for service recovery.	You can restore your backup data to the EVS, or use the backup as a data source to create an EVS for service recovery.

What are the differences between Cloud Server Backup and EVS Backup?

The main differences between Cloud Server Backup and EVS Backup are as follows:

Comparison Aspect	Cloud Server Backup	EVS Backup
Backup/restoration objects	Backup in the unit of a cloud server, that is, all EVSs (system disks and data disks) in cloud servers can be backed up.	Backup in the unit of an EVS, that is, a single or multiple EVS (system disks or data disks) specified can be backed up.
Recommended scenario	When you want to protect the entire cloud server for business stability and data security purposes.	Only when you need to back up personal data, private data, and important data in the data disks or system disks.
Advantage	Backing up the cloud server refers to the simultaneous backup of all EVSs on it, which ensures consistency and eliminates inconsistent data due to the time difference between backup creation.	Ensure data security at lower cost and at a finer granularity.

What are the differences between backup and disaster recovery?

Product	Application Scenarios	Purpose
Backup	Restore data to any backup point in case of software errors, virus intrusions, or accidental deletions.	Avoid data loss and restore data to the nearest backup point in case of fault.
Disaster recovery	Mainly used for dealing with issues from natural disasters such as fires and earthquakes. Therefore, make sure that there is a certain safe distance between the production center and the disaster recovery center.	Mainly used for avoiding business interruption. After a disaster occurs, the disaster recovery host can be activated in the disaster recovery center to ensure business continuity.

Are there quota limits on VBS?

Yes.

When the quota for VBS is insufficient, you cannot perform backups. The quota limits on VBS are as follows:

Limit Item	Quota (Default)	Method to Increase Quota
Number of repositories	10	Submit an order
Capacity of a single repository	100 GB-1,024,000 GB	Submit an order
Number of backup policies	20	Submit an order
Number of policies that can be bound to a single repository	10	Submit an order
Number of EVSs that can be bound to a single policy	200	Submit an order

What is the relationship between VBS and the repository?

VBS uses repositories to store backup copies.

Before creating a backup, you need to create at least one repository to put the backup copies generated by the EVS in the corresponding repository. Make sure that the backup copy size cannot exceed the repository capacity. For specific operations to create a repository, Creating a Repository.

How long does it take to back up an EVS?

The backup duration is related to the disk size and backup type. The larger the disk capacity, the longer the backup time. In general, the full backup takes a longer time than the incremental backup.

For example, depending on the number of tasks performed concurrently during backup, it takes about 20 to 50 minutes to back up 100 GB of data.

What can I do in case of exceptions in VBS?

Currently, exceptions in VBS typically include abnormal statuses of VBS. To address these issues, please refer to the measures below.

Exception Status	Suggestions
Error	Delete the VBS in the Error status and then re-create it.
Status lagging	Please contact our customer service staff to resolve this issue. Our customer service staff will take the initiative to help you solve this issue. Before that, we recommend that you do not perform other operations for the backup data. If you have requirements for customer service response speed, please feel free to contact us.

Volume Backup Service

General Issues