Help Center/ Migration Center/ FAQs/ Target Recommendations/ How Does MgC Generate Target Database Recommendations?
Updated on 2026-06-30 GMT+08:00
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How Does MgC Generate Target Database Recommendations?

MgC can assess and generate recommendations for MySQL, PostgreSQL, MongoDB, Oracle, and SQL Server databases.

The following table describes how the system recommends database versions and specifications during assessment.

Cross-version migration may fail if there are compatibility risks. Before the migration, evaluate risks and back up all data.

Table 1 Recommended versions for different databases

Database Type

Description

MySQL

If the source database version is earlier than 8.0, MySQL 5.7 is recommended. Otherwise, MySQL 8.0 is recommended.

PostgreSQL

The recommended target database version is preferably the same as the source database version. Note that PostgreSQL 12 and earlier versions are no longer available on Huawei Cloud. We will display all available versions on Huawei Cloud for you to choose.

SQL Server

The recommended target database version is preferably the same as the source database version. If the source one is no longer available, we will display all available versions on Huawei Cloud for you to choose.

MongoDB

The recommended target database version is preferably the same as the source database version. However, versions earlier than MongoDB 4.0 and later than MongoDB 5.0 are unavailable on Huawei Cloud. In this case, MongoDB 4.0 and MongoDB 5.0 are recommended.

Oracle

The recommended target database version is preferably the same as the source database version. If the source database version is missing, GaussDB V2.0-3.226 Enterprise Edition is recommended.
Table 2 Recommended specifications for different databases

Database Type

Instance Specifications

Instance Type

Storage Type

Performance Specifications

MySQL

Target database instances are recommended on a 1:1 ratio based on the CPU and memory sizes of source database instances. If the identical specifications are unavailable on the target platform, the system will apply a "minimum-equal" rounding-up rule to recommend the next available higher specifications. If any core data (such as the CPU count, memory size, or disk capacity) cannot be obtained, or if the source database instance specifications exceed the maximum limits available for sale on Huawei Cloud, the recommendation will fail.

For reliability purposes, the primary/standby instance type is recommended. The classic high-availability architecture with one primary node and one standby node enhances instance reliability.

Cloud SSD

For stable performance, Dedicated instances are recommended. Dedicated instances have dedicated CPU and memory resources, ensuring stable performance that is not affected by other instances on the same physical machine.

PostgreSQL

SQL Server

MongoDB

For source replica set or single-node instances, we recommend DDS replica set instances. For cluster instances, we recommend DDS cluster instances.

If the source database instance is a MongoDB replica set instance, the recommendation rules for the number of replica set instance nodes as follows:

  • Source instance nodes ≤ 3: A three-node DDS replica set instance is recommended.
  • 3 < Source instance nodes ≤ 5: A five-node DDS replica set instance is recommended.
  • Source instance nodes > 5: A seven-node DDS replica set instance is recommended.
    NOTE:

    Since Huawei Cloud supports replica set instances with up to seven nodes, source instances with more than seven nodes will still be mapped to a seven-node configuration. Check whether this meets your service requirements.

Ultra-high I/O

For stable performance, Enhanced II instances are recommended.

Powered by the second-generation Intel® Xeon® Scalable processors and featuring multiple technology optimizations, Enhanced II instances provide powerful and stable compute performance. Equipped with 25GE high-speed intelligent NICs, they offer ultra-high network bandwidth and PPS. As an excellent choice for heavy-load scenarios, this type of instance is suitable for websites, web applications, general databases, cache servers, and medium- and heavy-load enterprise applications that have high performance requirements for compute and network resources.

Oracle

For source RAC instances, we recommend distributed GaussDB instances. For other types, we recommend centralized GaussDB instances.

Ultra-high I/O

For stable performance, Dedicated instances are recommended. Dedicated instances have dedicated CPU and memory resources, ensuring stable performance that is not affected by other instances on the same physical machine.

Any missing key fields may cause the database assessment process to fail. The following table describes the fields required for database assessment.

Database Type

Required Field

Field Description

MySQL, PostgreSQL, SQL Server, Oracle, and MongoDB (replica set)

Version

Database version

CPU

Number of CPUs of the database instance

Memory

Memory size of the database instance

Disk size

Storage space of the database instance

MongoDB (cluster)

Version

Database version

Mongos node CPU

Number of CPUs configured for mongos nodes in a MongoDB cluster

Mongos node memory

Memory size configured for mongos nodes in a MongoDB cluster

Shard node CPU

Number of CPUs configured for shard nodes in a MongoDB cluster

Shard node memory

Memory size configured for shard nodes in a MongoDB cluster

Disk size of shard nodes

Storage space configured for shard nodes in a MongoDB cluster

Config node CPU

Number of CPUs configured for config nodes in a MongoDB cluster

Config node memory

Memory size configured for config nodes in a MongoDB cluster
Parent Topic: Target Recommendations