LJ blobs (images and audio) are now on a NetApp box
filesystem, completely apart from their user database cluster machines.
I didn't realise that this was a filesystem. It was constantly referred
to as a "NetApp" and I had no idea what it was, so I assumed it was some
sort of database or cache.
I also thought that functionally it was really just a cache, and I
thought the actual canonical data was still in the LJ database. Thanks
for clearing up that they are actually moving stuff out of the database.
But then again, the way LiveJournal handles userpics (or blobs in
general) makes backing up a consistent state easier for two reasons: (1)
The same blob ID is never used for different blobs. (2) The same blob,
for as long as it exists, is always found under the same ID.
Thus, all they need to do to back everything up is to back up the
database, and then the NetApp. Then you might have blobs in the NetApp
that aren't referenced in the database, but that's not nearly as bad as
having blobs referenced in the database that do not exist in the NetApp.
So, then, I guess Wikipedia could do that too.