External objects are not stored in Salesforce. So, it does not count towards your storage limit.
Use the below link to monitor storage and data resources
https://help.salesforce.com/articleView?id=admin_monitorresources.htm&type=5
As per the above link, External Objects are not included for storage calculation in Salesforce, so it won't take any space or storage from Salesforce.
Use the below link to monitor storage and data resources
https://help.salesforce.com/articleView?id=admin_monitorresources.htm&type=5
As per the above link, External Objects are not included for storage calculation in Salesforce, so it won't take any space or storage from Salesforce.
