Disk space in Parallels H-Sphere is allocated to customers through quotas, which are set separately for:
Quotas are obligatory plan resources and can't be disabled. Customers can't upload and store more MB than the resource quota allows (except for My/Pg SQL DBs) and will get an error message if they try to do so. If end users need to upload more MB than their resource quota allows, they can increase it. To keep users from increasing resource quota, it can be MAX restricted. This is done directly in plan edit wizards
All files with the owner's ID including those outside user's home directory (e.g. Transfer, Referrer, Agent and Error logs that are used for user website statistics) are counted toward used disk space. That's why quota usage may be different from the size of the user home directory.
Important: when creating a plan for MS SQL DB's service, don't set MS SQL quota of 0MB, as just created MS SQL databases already contain system information of 2MB (for MSSQ 2000) or 3MB (for MSSQ 2005) of disk space!
Summary Disk Usage
Every 24 hours a cron script scans end user's FTP home directory, all mailboxes, and DBs to summarize the disk space and make up summary disk usage for the last day. Summary readings of each daily scan are added up and divided by days elapsed from the beginning of the billing month. The resulting amount makes up user's average summary disk usage.