On one server, i did run remove_unknown (took 3 days), it then became slow.
As in too slow to cope with the backup rhythm, the backup went from like 1-2 minutes to 20-30 minutes (x264 servers, that were backup up 4x per day before)
I did then run defrag-database ( took 4 hours) thinking there were too much changes and it would need some maintenance.
After the defrag, the database file was twice as large as before (15gb to 30 gb)
i think it is now in startup maintenance or schema upgrade (showing number of entries processed + percentage at 6.5M files/48%, started 3 hours ago )
The other server which was also updated but on which remove_unknown wasn’t run has normal backup speed. (maybe the problem isn’t actually with remove_unknown)
One of the thing which is slow is :
Referencing snapshot on “xxx” for path “yyy” failed: FAILED
About 1-2 line get printed every second but there s a lot of lines that get printed.
Maybe it is one line per path stored in the .directory_pool ?
So this one is very noticable, because the actual backup is often <1min, but that last step with run during 2-3 minutes.