Data　placement　considerably　affects　the　I/O　performance　of　distributed　storage　systems　such　as　HDFS.　An　ideal　placement　algorithm　should　keep　the　I/O　load　evenly　distributed　among　different　storage　nodes.　Most　of　the　existing　placement　algorithms　with　I/O　load　balance　guarantee　depend　on　the　information　of　data　popularity　to　make　the　placement　decisions.　However,　the　popularity　information　is　typically　not　available　in　the　data　placement　phase.　Furthermore,　it　usually　varies　during　the　data　lifecycle.　In　this　paper,　we　propose　a　new　placement　algorithm　called　Balanced　Distribution　for　Each　Age　Group　(BEAG),　which　makes　data　placement　decisions　in　the　absence　of　the　popularity　information.　This　algorithm　maintains　multiple　counters　for　each　storage　node,　with　each　counter　representing　the　amount　of　data　belonging　to　a　certain　age　group.　It　ensures　that　the　data　in　each　age　group　are　equally　scattered　among　the　different　storage　nodes.　As　the　popularity　variance　of　the　data　belonging　to　the　same　age　group　is　considerably　smaller　than　that　of　the　entire　data,　BEAG　significantly　improves　the　I/O　load　balance.　Experimental　results　show　that　compared　to　other　popularity　independent　algorithms,　BEAG　decreases　the　I/O　load　standard　deviation　by　11.6%　to　30.4%.