What happens if out of SharePoint Storage at tenant level

[CaptainReboot]

Hey all,

I'm helping a customer migrate their SharePoint/Teams sites to a new tenant. The current tenant is out of SharePoint storage and it's been like that for months. Everything still works though. My understanding is that at the site level, if a site has reached it storage quota, it's in read only.  I can't find anything on what happens though when the storage is at capacity at the tenant level.  Since it's been working for months, will it eventually break?

[#2]

Not sure what happens if tenant storage is full . Normally if site storage is full we see files can not be edited , can not upload new files .

But not able to find any details how tenant behaves storage is fully used. Better to reach Microsoft and increase storage before something happens to data.

Else deleted sites that are not using from long time and reduce versions on site which may help.