[throwawasiudy]

Sounds like it to me. Storing a crap ton of 300 byte messages is pretty common. Thousands of companies have been doing it for a decade. Anyone that does analytics or email probably stores far more of these than twitter.

Blob store is perhaps the only forgivable custom solution. Besides the eventually expensive S3 you pretty much have to roll your own large binary storage at that scale.

For regular DB sized workloads 1-16k bytes they had hundreds of options to choose from. Same with caching. They're both relatively solved problems.