When I Migrate a Windows Source Server from Alibaba Cloud, Why Do I Need to Choose a Target Disk at Least 1 GB Larger than the Paired GPT Source Disk?

Scenario

You wanted to migrate a Windows server from Alibaba Cloud. The server had a 40-GB GPT disk, and the disk only had a single partition. When you configured the target server, you chose a 40-GB disk as the disk pair, and the system displayed the message "Some disks on the target server are smaller than those on the source server. Select another target server." The size recommended for this target server disk is 41 GB.

Possible Causes

When a disk is formatted using GPT, an MSR partition is automatically generated. This partition is invisible to users and can only be viewed using DiskPart.

On Alibaba Cloud, an MSR partition occupies 15 MB.

On Huawei Cloud, an MSR partition occupies 128 MB.

When a GPT disk is migrated from Alibaba Cloud to Huawei Cloud, 113 MB more space needs to be reserved for the MSR partition. In addition, EVS requires that disk capacity be expanded in increments of 1 GB. Therefore, the paired target server disk must be at least 1 GB larger than the source GPT disk.

Solutions

• Solution 1

  Expand the capacity of the target server disk to be at least the size recommended by the system.

• Solution 2

  Shrinking the source disk partition.