this is a desirable property of distributed system with replicated data
C: consistency, sabhi jagah same data rahna chahiye (i.e DB node B, DB node C is in sync)
A: Availibility, ateast server response karna chahiye
P: Partition Tolerance: (DB Node B and DB Node C partition ho gya hai fir bhi …. system up hai, user able to query and getting the data)
why we can not use all 3 together
CA : available bhi rahe consistant bhi rahe then jab bhi partition hoga server ko down karna hoga hence no partition tolerance
CP : data consistant rahe and partition tolerance rahe then we need to down the server hence that particular node will not no available
AP : Available bhi rahe and partition tolerance (i.e 2 node kai bich connecton break hone kai baaad bhi wo node up rakhne hai then data consistance nhi rah payega)
CAP: Not possibe
in current world we don’t trade off Partition tolerance (i.e our system will up even after break in connection between two internal node)
now system will will CP or AP