Sleep through the night

My 8 months old baby is still waking up twice every night for feeding. he goes to bed at around 7:30pm, then he would wake up around 1:30am to nurse, and once more around 4am also to nurse. how can I get him to sleep longer or through the night. how long should an 8 months old baby sleep without feeding. I tried few time to just calm him down without feed when he wake around 1:30am but he just just started crying until I breasfed him than he slept. please help with any suggestions