Because the native behavior and part of the origin story of a Dell SC is that it use thin provisioning on default. Also the incoming and existing data is protected(stored) by different RAID Level (depends on the selected storage profile) like RAID 10 for new/changed and RAID5or6 for cold data. So the space requirement for storing 1TB of user data are based on multiple variables and makes it unpredictable. In wort case you have to calculate 2 or 3TB(RAID10 DM) for storing of 1TB user data. Oh... and we have not spoken about snapshot consumption. The Dell Compellent is a pool of storage resource and will dynamically assign the resources where needed. Regards,Joerg
Dear, We have SCv3020 and there are 10 more volumes. The whole storage stucked and emergency mode when only one of the Volumes was full. Could u please explain this.          
SCv3020 volume space