> elasticache is just vanilla redis

Only at the interface level. Elasticache is a heavily forked Redis. There's a reason it's several versions behind.

that makes sense. i guess i had just assumed it was laziness. :-)

out of curiosity, do you have any idea what their mods might be?

I never bothered to really look into it -- I suspect it's semi-public information. If I had to guess, lots of internal changes to make Redis behave better in AWS's architecture to do with containerization, EC2, S3/EBS, maintenance automation related stuff, instrumentation, etc.

Oh actually definitely some stuff related to their redis clustering system.

They also support encryption in transit. That part was open sourced recently, but hasn't made it into upstream yet (though it most likely will from sounds of it).