Unlike Memcached or Redis, RAMCloud provides durability:
* Automatic replication, crash recovery, and fail-over
(no loss of availability if a server fails)
* Durability guarantee: data is always replicated
and durable before operations return, without
significant performance hit (subject to the
requirement for persistent buffers on backups).
You can't make a durable write to disk in 15us. SSDs are around 2 orders of magnitude slower than that. 15us is about right for in memory on two nodes in a single data center though. Most people wouldn't consider that durable though.
Comments
Unlike Memcached or Redis, RAMCloud provides durability:
You can't make a durable write to disk in 15us. SSDs are around 2 orders of magnitude slower than that. 15us is about right for in memory on two nodes in a single data center though. Most people wouldn't consider that durable though.
So? Power goes out in your data center, all the data is lost.
Nothing stops you from replicating memcached.