Compaction during rebalance, doc clarification

Colleagues,

  1. please clarify if
    "If you perform a rebalance while a node is undergoing index compaction, you may experience delays in rebalance." from http://docs.couchbase.com/couchbase-manual-2.5/cb-rest-api/#adjusting-rebalance-during-compaction

refers to the process of compacting these files:
/opt/couchbase/var/lib/couchbase/data/$BUCKET/.couch.

we’re confused by this “index compaction” phrase, since /opt/couchbase/var/lib/couchbase/data/ are not “index files”, those are bucket persistence files.

  1. our ultimate goal is to understand if compaction of persistence files is affected by rebalance. it seems “yes”.
    we want to estimate the volume of /opt/couchbase/var/lib/couchbase/data/ required to accommodate not only usual usage, but also usage during rebalance.

Alexander, Russia, Moscow