Do EVS backup operations affect the EVS performance?
Backup operations have little impact on the EVS performance.
The backup mechanism is as follows: When backing up an EVS, the system will create a snapshot for the EVS and obtain the data to be backed up using the EVS snapshot. However, the data will not be directly read from the EVS. To this end, backup operations have little impact on the EVS performance.
Do I need to stop the Elastic Cloud Server (ECS) when backing up an EVS?
No.
You can decide whether to shut down the ECS when backing up an EVS according to your own needs.
Theoretically, you can back up eSurfing Cloud EVSs when the ECS and EVS are in use without the need to stop the ECS.
When the cloud server is running normally and the EVS is reading and writing normally, some data is stored in the EVS while part of the latest data is stored in memory as cache data. During backup operation, it is important to consider that this part of cache data will not be automatically written to the EVS, which may lead to inconsistent backup data.
Therefore, we recommend that you suspend the data writing before backing up or suspend the operation of the application system. In addition, it is advisable to conduct backups in off-peak periods, such as early in the morning. If you have higher integrity requirements for backup data, you can also select to directly shut down the cloud server for offline backup.
Can VBS select a partition of the EVS for backup?
No. VBS is built upon the EVS for backup purposes, meaning the entire disk is backed up without the option to further divide it into partitions for backup.
If you need to backup a partition of your EVS, we recommend that you use the Cloud Backup & Recovery service. Cloud Backup & Recovery (CBR) is an easy-to-use, cost-effective, safe, and reliable backup solution, which only requires one click. The centralized management interface offers unified data protection for resources like directories and files in cloud servers hosting user services within eSurfing Cloud.
Can an EVS be backed up across regions?
No.
An EVS can only be backed up within a region. After you create a backup, you can use it to perform one of the followings:
l Restoring Data to the Source EVS.
l Creating an EVS. The regions of the new EVS and the source EVS must be the same, but their AZs may be different.
Why would the backup capacity be greater than the usage capacity seen in the operating scenario?
l Scenario
A large number of files are stored on the server, and a backup is made after deleting some of the files. However, the backup capacity is greater than the usage capacity viewed in the operating system.
l Cause
The eSurfing Cloud VBS is a block-level backup at the storage layer. It backs up the used data blocks from block storage and does not recognize file changes within the operating system. When the operating system deletes files, it merely creates deletion marks in the file attributes without erasing the data in the block device (setting the data block to 0). Since the block backup cannot perceive the deletion marks at the operating system layer, it decides whether to perform a backup solely based on whether the data blocks are all zero.
l Suggestions
We recommend that you use a third-party disk cleanup or erasing tool to clean up the EVS (The tool provider is responsible for ensuring the security/availability of the tool).
Why does the deletion of backups result in only a slight change in the remaining space of the repository?
In actual use, it is possible for the displayed remaining space of the repository to show no change after backups are deleted.
Such an issue can be attributed to several factors:
l The underlying backups of EVS are deleted asynchronously. When the backup is deleted, the underlying backup data will be deleted gradually in a short period based on the backup size.
l By default, the initial backup of VBS is a full backup, while subsequent backups are incremental backups, which only capture changes. If a deleted backup was an incremental one, it might occupy minimal space.
Can I back up data from two EVSs to one backup?
No.
An EVS can create multiple backups, but backing up data from two EVSs to the same backup copy is not supported.
You can achieve this indirectly by copying the data in EVS A to EVS B and backing up EVS B after the copy is completed. By doing so, the final backup contains data from both EVS A and EVS B.
How do I copy the data of an EVS in the same region and AZ?
1. Under one region, create a repository.
2. Create an EVS backup for the EVS to be copied.
3. In the Backup Copy list, use the created backup to create a disk. When creating a new disk, you can select the same AZ, thereby copying the EVS data in the same region and AZ. See Using Backups to Create an EVS.
Will deleting the created EVS backups damage the performance of the cloud server?
No.
EVS backups are not stored in the cloud server, but not on the object storage service (OSS). Therefore, deleting them will not affect the performance of the cloud server.
Note: The backup cannot be retrieved after deletion. Please operate with caution.
Can I still use VBS to restore the source EVS data after the source EVS is deleted?
You can restore data by either restoring it to the source EVS or using backups to create an EVS.
l When the source EVS is deleted, the data cannot be restored to the source EVS.
l When the source EVS is deleted, it is possible to create an EVS to restore the data. EVS resources and EVS backups are not stored together but exist independently. Deleting EVS resources will not delete the EVS backups. You can use backups to create an EVS, which has the backup data in its initial status.
How many EVS backups can one EVS create?
There are no limits. As long as the remaining capacity of the repository is sufficient, you can create backups for any EVS. You can choose an appropriate backup solution based on the specific business and budget requirements.
The differences between Back up Now and Automatic Backup are as follows:
Comparison Item | Back up Now | Automatic Backup |
Backup policy | Not Required | Required |
Number of backups | Manual one-off backup | Automatic periodic backup based on the backup policy |
Number of EVSs that can be backed up at a time | Multiple | Multiple |
Backup name | Customization supported | Automatically generated by the system |
Backup method | Full backup initially and incremental backup subsequently | Full backup initially and incremental backup subsequently |
Recommended application scenarios | Executed before patching or upgrading the operating system or upgrading an application on a cloud server. This ensures quick restore to the original state in case of patching or upgrading failure. | Executed for routine backup protection of an EVS. The latest backup can be used for restoration in case of unexpected faults or data loss. |
Can I still use incremental backups to restore data after a full backup is deleted?
VBS does not distinguish between full backups and incremental backups when restoring data. It can restore the full data of an EVS from any backup. Deleting a specific backup will not affect the ability to use other backups for data restoration.
Example: The EVS generates three backups a, b, and c in chronological order, with each backup capturing data changes. After Backup a is deleted, Backup a and Backup c can continue to be used for full data restoration.
Can I terminate an EVS backup in progress?
No. Currently, the EVS backup task in progress cannot be terminated.
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. If a backup task remains incomplete for an extended period, you can contact customer service for assistance in resolving the issue.
How do I view the data in an EVS backup?
You can achieve this indirectly by:
1. Using backups to create an EVS. For specific operations, see Using Backups to Create an EVS.
2. Attaching a created EVS to the cloud server in the same region and the same AZ. For details, see Attaching an EVS.
3. Logging in to the ECS to view the data in the EVS.
How long does an EVS backup be retained?
VBS supports manual backups and automatic backups.
l Manual backup: Under normal circumstances, manual backups will be retained until manually deleted by users or automatically released due to insufficient account balance.
l Automatic backup: Automatic backups are typically periodic backups created automatically based on a backup policy. The retention time for such backups depends on how you configure the retention rules when presetting the backup policy. You can set the retention rule to By Time, By Number, or Save Perpetually.
Does VBS support simultaneous backup of all EVSs in the cloud server?
Yes.
VBS supports simultaneous backup of multiple EVSs, whether for manual one-off backups or periodic backups based on a backup policy. These EVSs can originate from the same cloud server.
Implementation method: In Bind Elastic Volume Service with backup policy, simply select multiple EVSs. For specific operations, see Creating an EVS Backup.
Can I back up an EVS multiple times per day?
Yes.
The EVS backups are divided into manual backups and automatic periodic backups based on a backup policy.
l Manual backup have no limits on the number of backups you can execute per day.
l For periodic backups based on a backup policy, you can execute a backup at any hour of the day. Up to 24 times of backup can be performed per day with an interval of one hour.
Can a backup copy be downloaded locally?
No. The EVS backup data cannot be downloaded locally.
If you have specific requirements, feel free to reach out to our product pre-sales manager or solution manager through customer service phone lines and other means. We will tailor suitable solutions for you based on your business needs.
Can I back up an EVS containing an application system?
Yes.
For applications with consistency requirements such as databases or mail systems, we recommend that you suspend all data write operations before backing up.
If the write operation cannot be suspended, you can shut down the application system or the cloud server for offline backup.
Will VBS back up shared disks?
Currently, VBS cannot back up shared disks. However, this functionality will be gradually enhanced in the future.
If you have specific requirements, feel free to reach out to our product pre-sales manager or solution manager through customer service phone lines and other means. We will tailor suitable solutions for you based on your business needs.
Can I restore a system disk using backups?
Yes.
You can restore a system disk using backups. Before that, you need to uninstall the system disk from the cloud server or shut down the cloud server.
Alternatively, you can create an EVS through a system disk backup. However, the created EVS cannot be used as a system disk for the time being.
Can data be backed up when the EVS expires?
No.
You cannot create a new backup when the EVS expires. The backup and restoration jobs in progress will continue at a low speed when the EVS expires. We recommend that you pay attention to the expiration time of the EVS and renew your subscription in time to guarantee normal business operation.
Why are the capacities of the backup copy different when data on the same disk is backed up? Why is the capacity of the backup copy smaller than the actual data size on the hard disk?
Volume backup service usually includes full backup and incremental backup, and the volume backup service will compress data and then store it in the ZOS. The first backup of a resource is a full backup by default, i.e., all data of the EVS will be backed up. For each successive incremental backup, only the changes made to the previous backup are backed up. Therefore, incremental backups require less storage space than full backups, and in some cases, even require storage space smaller than the actual data size on the EVS.
Both full and incremental backups can recover all data on the EVS. You can restore a backup copy with a small amount of data to a new disk and check whether data on the new disk is different from that on the original disk to verify data integrity.
Why does the volume backup service compress the backup data?
The volume backup service compresses backup data. Data is automatically compressed while being backed up to reduce storage space usage and improve backup efficiency. This method can be applied during backup to ensure that the size of the backup data is optimized to save storage resources.
Data is compressed in both full backups and incremental backups and the compression ratio differs depending on data type.