Migration shows the following warning: Insufficient disk space on the destination server to transfer all the selected subscriptions

Symptoms

• The following warning is shown during a Migration:

  Insufficient disk space on the destination server to transfer all the selected subscriptions. Available: 14753 MB. Required: 235603 MB. Note that the required space is calculated as a sum of web, mail, and database contents of domains. The required space is calculated once a day and stored in cache, so the actual size of domains might differ from the calculated size. If you make sure that the selected domains do not occupy more space than available, you can proceed with transfer.

• There is not enough space in the / partition to write 235603 MB. Only 14753M are available.

  # df -BM
  Filesystem 1M-blocks Used Available Use% Mounted on
  udev 8003M 0M 8003M 0% /dev
  tmpfs 1605M 33M 1572M 3% /run
  /dev/sda1 20029M 4236M 14753M 23% /
  /dev/sda2 204800M 500M 204276G 1% /var

Cause

Plesk Migrator calculates the available space on the root partition only, but the partition for /var has enough available space.
This has been reported as bug #PMT-4749 

Resolution

The warning can be safely ignored.