The new usage model
The first thing administrators will notice is they reclaim a lot more SharePoint Online pooled storage. This is because the concept of reserved storage now only applies at the tenant level for SharePoint Online. For example, if you had a site collection’s storage quota set to 100 GB in the old model and were only using 20 GB, it now has a usage limit of 100 GB in the new model, and returns 80 GB back to the tenant storage pool. Site collections (other than OneDrive) no longer tie up blocks of reserved storage. Instead, only the actual storage used counts against total pooled storage.
How the new usage model applies to team sites and OneDrive for Business.
Auto versus Manual
The second thing admins will notice is the new Site Collection Storage Management toggle switch within the SharePoint Online admin center, under the settings tab. Auto enables hassle-free storage management, while Manual enables the admin to apply storage usage limits per site collection (excluding OneDrive).
The Site Collection Storage Management toggle switch to select Auto or Manual.
New customers are set to Auto by default, with the ability to switch to Manual at any time. Auto enables you to auto-matically pull from your available SharePoint Online pooled storage for any and all of your site collections (more on pooled storage below). Your site collections only use what they need from the available pooled storage, automatically, up to whatever the current maximum system limit is per site collection—currently 1 TB.
When you select Auto for Site Collection Storage Management, all site collections adhere to the auto-grow usage mode.
When the new usage-based storage model rolls out, all existing customers will be in “Manual” mode by default and can easily opt-in to Auto. Manual allows the admin to set usage limits per site collection. All previously configured storage quota values that existing tenants have in place prior to rollout will persist in the new model (under Manual), but be represented as storage usage caps.
If you manage storage for your site collections manually, site collections will adhere to individual usage cap limits.
Whether you select “Auto” or “Manual,” managing SharePoint Online quota is now worry free. You don’t have to worry about management overhead or “lost” storage that has been allocated but not used. Furthermore, this means you can create as many site collections as you want without being limited by whether there is storage available to allocate.
Site Collections limit, pooled storage and additional storage
Not only have we simplified storage management in SharePoint Online, but we increased the maximum number of site collections SharePoint Online supports per tenant. We’re announcing today that individual Office 365 tenants can now have up to 500,000 site collections (up from the previous limit of 10,000) and they all draw from the same pool of storage as described above.