This is a great deck, but I'd love to see one on how we can use Redis at Heroku; it looks like the options are (a) Redis To Go, which is unreasonably expensive, and (b) an insecure connection to an m.large at EC2.
I'm unwilling to trust IP access control for anything in 2011.
If I could do SSH port forwarding, that'd probably be my first choice. I have a AES-128-CTR+HMAC-SHA256 encrypted sleeve for the Redis protocol with an attendant Redis::Connection driver, but this is exactly the kind of thing I'm always telling people not to do.
This motivated me to play around with Net::SSH port forwarding this afternoon and evening. What I ended up with was a tiny patch that allows you to forward a local UNIX domain socket to a remote TCP port over an SSH connection. It's a fun hack if nothing else:
Secure meaning there is a private back-end network or there is some form of tunneling/encryption end-points available and enabled by default for instances?
Here's the current AWS security guide that I was able to find:
"On the Heroku dyno manifold, each and every process has full isolation from all other processes, including those of the underlying operating system and other processes from the same application. This provides complete protection from either of the circumstances above, and many others."
Based on that, do we presume they are also using routes and not bridges?
- Redis is a DSL for persistent data structures and a network server, which exposes it.
- ETS (Erlang Term Store) is an optimized native in-memory lookup table [1].
- DETS (Disk ETS) is the same as ETS but with disk persistency. There is some limitations on the size of database.
- Mnesia is a distributed/replicated STM built on top of ETS/DETS.
You can think about ETS/DETS as a lightweight Redis without network interface.
ETS/DETS support much less data structures, than Redis, i.e. only sets, ordered sets, bags, duplicate bags. Redis supports strings, lists, sets, sorted sets, hashes, etc.
Redis is much more featured, than ETS/Mnesia.
Both have different scalability profiles.
Using Mnesia in distributed cluster effectively places a limit on the number of nodes in cluster (tens).
Clustering support for Redis is not yet released. Most production installatons using Master-Slave replication and/or sharding.
On raw single node request/s metric Redis is faster than Mnesia.
Redis is single-threaded, while Mnesia can utilize SMP and clusters.
I would like to see Redis stripped of TCP network interface and integrated in the same way as ETS in Erlang.
