I am not convinced, as the consumer conducts a search operation on the log database and not a sync operation, unless the consumer maintains a local logdatabase. But others may clarify this.
There is replication information stored in the log database that is maintained by the syncprov overlay. Thus, it is required for it to be present. And that's why you were getting a very explicit error about the overlay not being present when it was searching the log database. But you can ignore your errors if you want.
Note the contextCSN stored in the accesslog DB: # accesslog dn: cn=accesslog structuralObjectClass: auditContainer entryCSN: 20101123115530.669034Z#000000#000#000000 contextCSN: 20101130203425.474878Z#000000#000#000000 entryDN: cn=accesslog subschemaSubentry: cn=Subschema hasSubordinates: TRUE --Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration