Is it Sunnah to fast the entire month of Sha’ban?

It is recommended to increase fasting in Sha'ban. Scholars have differed regarding whether the Prophet, peace and blessings be upon him, fasted the entirety of Sha'ban. Some are of the view that he sometimes fasted it completely and at other times fasted most of it. Others held that he never completed fasting an entire month other than Ramadan, and they interpreted the hadith of Umm Salamah to mean that he fasted most of it, saying that Arabs use the phrase "fasted the entire month" to refer to someone who fasted most of it.

As for the wisdom behind increasing fasting in Sha'ban, the Prophet, peace and blessings be upon him, mentioned that it is a month people are heedless of, between Rajab and Ramadan, and in it, deeds are raised to the Lord of the Worlds. So he loved that his deeds be raised while he was fasting.