[dingo_bat]

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.

[martincmartin]

"The simplified data schema directly reduced the size of data on disk. We saved additional space in MyRocks by applying Zstandard, a state-of-the-art lossless data compression algorithm developed by Facebook. We were able to reduce the replication factor from six to three, thanks to differences between the HBase and MyRocks architectures. In total, we reduced storage consumption by 90 percent without data loss, thereby making it practical to use flash storage."