Erasure　coding　has　been　increasingly　used　by　distributed　storage　systems　to　maintain　fault　tolerance　with　low　storage　redundancy.　However,　how　to　enhance　the　performance　of　degraded　reads　in　erasure-coded　storage　has　been　a　critical　issue.　We　revisit　this　problem　from　two　different　perspectives　that　are　neglected　by　existing　studies:　data　placement　and　encoding　rules.　To　this　end,　we　propose　an　encoding-aware　data　placement　(EDP)　approach　that　aims　to　reduce　the　number　of　I/Os　in　degraded　reads　during　a　single　failure　for　general　XOR-based　erasure　codes.　EDP　carefully　places　sequential　data　based　on　the　encoding　rules　of　the　given　erasure　code.　Trace-driven　evaluation　results　show　that　compared　to　two　baseline　data　placement　methods,　EDP　reduces　up　to　37.4%　of　read　data　on　the　most　loaded　disk　and　shortens　up　to　15.4%　of　read　time.　©　2016　IEEE.