Things are slowly returning to normal. Searching and browsing on PhotoDune is only showing some of the items, but the rest should appear gradually over the next hour or two.
Here’s the short version of what happened:
We have two servers in charge of search, and each of those has two copies of all the data needed for search. Somehow both copies on the master server got corrupted, and the corruption spread to the other server, leaving us with no working search data at all!
To be clear, all the items are still there, and no data was lost. The problem only affects the indexes we use for search.
We’ll do a post-mortem in the morning and work out what went wrong, and no doubt we’ll add some more safeguards to make sure that this doesn’t happen again.