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  5. Differences Among EVS Disk Backup/EVS Snapshot/EVS Replication

Differences Among EVS Disk Backup/EVS Snapshot/EVS Replication

EVS disk backup, EVS snapshot, and EVS replication all provide redundancies for the EVS disk data to improve data reliability. Table 1 lists the differences among them.

Table 1 Differences among EVS disk backup, EVS snapshot, and EVS replication

Metric

Storage Solution

Data Synchronization

DR Range

Service Recovery

EVS disk backup

The backup data is stored in the OBS service, isolated from the EVS disk data.

Saving the EVS disk data at specific time points

The backups and disks must be in the same region, but can be in different AZs.

Data can be retrieved and services can be restored by restoring the backup data to original disks or creating new disks from backups.

EVS snapshot

The snapshot data is stored with the disk data.

NOTE:

It requires a certain period of time to create a backup because data needs to be transferred. Therefore, creating or rolling back a snapshot consumes less time than creating a backup.

Saving the EVS disk data at specific time points

Same AZ as the EVS disks

Data can be retrieved and services can be restored by rolling back the snapshot data to original disks or creating new disks from snapshots.

EVS replication

Data in the DR disks is stored in the data center of another AZ.

Synchronizing the data with production disks in real time

NOTE:

DR disks can synchronize the data with production disks in real time, achieving a Recovery Point Objective (RPO) of zero and ensuring tight consistency between production data and replication data.

Different AZs with no more than 100 km in physical distance

NOTE:

You can specify the secondary AZ, and the distance between the data centers in the primary and secondary AZs must be less than 100 km.

Services are restored directly by the existing DR disks and DR servers.

If the primary AZ is faulty, services in the primary AZ will be stopped, and DR resources in the secondary AZ will be enabled to restore services.

NOTE:

EVS replication APIs have been deprecated. If you need to use the replication function, see Storage Disaster Recovery Service User Guide and Storage Disaster Recovery Service API Reference.