Lost Indices?

(from github.com/MeMeLwin)
Already crawled and perfectly worked for a while but suddenly cannot show result when searching…
Turns out the indices are lost…
Re-crawling solved the current problem…
But want to know the reason why indices are lost without manually deleting them…

(from github.com/marevol)
Did you check Remove Documents Before?

(from github.com/MeMeLwin)
General-> Remove Documents Before=3 days (default)
The window server which the fess is running was re-started due to window update…
The indices are deleted after 3 days according to the “Remove Documents Before” setting.
I think I understand the reason…
Thank You :dancer: