[Tariq Rashid]
so is the new Data.fs.index regenerated when Zope is restarted?
If you copy over the .fs file but not the .index file too, then it's best practice to delete the stale .index file (if any) on the destination machine. ZODB uses some heuristic checks to try to detect a mismatching .index file, and they're pretty strong heuristics, but it's possible they could fail to detect a mismatch.
ps - i've migrated Data.fs successfully and repeatedly between a netbsd 2.0 install a linux server withand i didn't copy the .index file,only the Data.fs)
It's always OK to delete an .index file. ZODB creates an .index file if none exists. Leaving behind a stale .index file is a little risky. I expect it's much riskier to leave stale persistent ZEO cache files in place, if the destination machine is being used as a ZEO server.