Redis vs RDBMS

Following is a list of differences between Redis and RDBMS:

Redis	RDBMS
Redis stores everything in primary memory.	RDBMS stores everything in secondary memory.
In Redis, Read and Write operations are extremely fast because of storing data in primary memory.	In RDBMS, Read and Write operations are slow because of storing data in secondary memory.
Primary memory is in lesser in size and much expensive than secondary so, Redis cannot store large files or binary data.	Secondary memory is in abundant in size and cheap than primary memory so, RDBMS can easily deal with these type of files.
Redis is used only to store those small textual information which needs to be accessed, modified and inserted at a very fast rate. If you try to write bulk data more than the available memory then you will receive errors.	RDBMS can hold large data which has less frequently usage and not required to be very fast.