Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) used to pray eight rak'ahs at night, whose bowing and prostrations were as (long as) their recitation, and he would say the salam after every two rak'ahs.
Al-Tabarani recorded it in al-Mu'jam al-Awsat. Its chain contains a narrator, Junadah bin Marwan, whom Abu Hatim held suspect (muttaham).