They say that they brought some new search features to mobile, though I would prefer if they fixed their search on desktop (or in general) first, as it only returns results from recent messages.

Until sometime in 2016/2017 it was possible to look for specific things at whatever time (e.g. 2011) and now even things from <3y ago don't return anything.

Whatever you may think of social networking, Facebook takes huge amount of pains to ensure reliability. They moved all the data from spinning disks to flash, also migrating to a new db. No downtime at all.

I'm a bit unclear as to how this process resulted in 90% decreased storage use.

Facebook has been using RocksDB more and more (now messenger, but also Instragram’s flavor of Cassandra). I wonder if Google has a similar penetration of LevelDB (and we just don’t hear about it because Google’s infrastructure work isn’t open source)

During the dual-write phase, what happens if one request succeeds while the other doesn't?

What about giving me an easy option to export my messages while you are at it?

TL;DR - Moved from HBase to MyRocks engine on MySQL sitting on top of NVMe storage via their Lightning Server [1], which is a JBOF (just a bunch of flash) setup using x16 PCIe.

[1] https://code.facebook.com/posts/989638804458007/introducing-...

Great, now they can serve video ads in Messenger more easily.