Find size limitation for all attributes in user objects in Active Directory

1) Login to Active Directory connector server
2) Open the powershell and run the below mentioned command.

dsquery * "cn=Schema,cn=Configuration,dc=YOURDOMAIN,dc=COM" -Filter "(objectClass=attributeSchema)" -Attr LDAPDisplayName rangeUpper -Limit 0 >  C:\Users\oimadsvc\Downloads\Report.txt

your Report.txt will be saved in location C:\Users\oimadsvc\Downloads will be having the required information of size limits of all the attributes.