With 2 connections per range the prefetcher needs 20+ ranges with chunks left; fully spooled ranges counted as ready (SPOOL_AHEAD_PER_LEASE) but take no connection, so on small ranges 30 of 40 connections were busy (13-15 ranges). Fresh ranges now also fill up to loops/perRange + 2 ranges being fetched. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>