Unable to select the same deployment size when upgrading vCenter Server

Products

• VMware vCenter Server

Issue/Introduction

 

• When upgrading from vCenter Server 7.0 to 8.0 or 8.0 to 9.0, the installer does not allow selecting the same deployment size as the source version.
  
  
  
• The upgrade wizard shows that the source machine's storage size is larger than the destination's.
  
  

Environment

vCenter 7.x

vCenter 8.x

vCenter 9.x

Cause

In the current implementation, if the total disk layout size of the upgrade target is smaller than the provisioning size of the source vCenter Server Appliance, you cannot select that deployment size during upgrade.  
The disk layout size on the target side does not include snapshot files, swap files, log files, and some hard disks.
Since the disk layout sizes for vCenter 7.0, 8.0 and 9.0 only differ slightly, this difference often causes the provisioning size of the source vCenter Server Appliance to appear larger.

Resolution

In the current implementation, this is expected behavior.

Please refer to the following steps as a workaround.

1. Proceed with Stage 1 as a "Install" instead of an "Upgrade" and select the same deployment size as source vCenter Server 7.0.  
   
   
   
    Note: Leave FQDN empty and specify a temporary IP address in the IP address field.
   
   
   
   
2. Start Stage 2 via VAMI at https://<vCenter_temporary_IP_Address>:5480 .  
   
   
3. From Stage 2, select "Upgrade" and enter your source vCenter Server information.