What does ssd-2 mean? Is it perhaps the second generation of the SSD storage engine? I don’t see it specifically mentioned in the docs, but some of the doc examples show ssd and others show ssd-2.
ssd is an alias for ssd-2. There’s not a huge difference between the two. ssd-2 has better behavior with storing large values in overflow pages in the sqlite b-tree than ssd-1 and adds page checksums for better data corruption detection. As ssd-2 is strictly better than ssd-1, there’s not really any reason to run with ssd-1, but for upgrade reasons it was left in.
A quick grep only shows hits on the administration page, which also looks like output from fdbcli> status. Was there anywhere else that you saw it?