- Plesk 11.x for Windows
- Plesk 11.x for Linux
The Disk space can not be set to 2.5 GB ( or 2560 MB ) on service plan. After applying the settings it is get rounded to 3GB.
Such behavior is considered to to be a software issue PPPM-754 .
The issue is fixed in Plesk 12. Upgrade your Plesk by using KB #213411749 to avoid the issue.