Back when I created my SharePoint farm, I decided to rename the personal site quota template to something like ‘Personal Site (1GB)’. I did this because I wanted the size of the quota in the name – the out of the box one is just called ‘Personal Site’.
What I noticed after doing this is that none of the My Sites that were being created were having a quota applied. They would be set to ‘Individual Quota’ with no limits applied. Not good.
The cause of this is that SharePoint does not look at the default quota that is set on the My Site web application:
Central Admin –> Application Management –> Web Application General Settings –> Default Quota template
Central Admin –> Application Management –> Manage Web Application –> Select Web Application –> General Settings (ribbon) –> Default Quota Template
It is hard-coded to use the template called ‘Personal Site’.
So, make sure that you have a quota template called ‘Personal Site’. If this quota template has been removed or renamed, no quota is applied.
UPDATE (2/8/11): This also applies to SharePoint 2010. Added path to configuration setting in SP2010 Central Admin.