What is the test for determining whether a prison official was deliberately indifferent to the safety of an inmate?

However, before determining whether a prison official was "deliberately indifferent," the constitutional deprivation alleged must be objectively, 'sufficiently serious'." (Id.) (citations omitted). The Eighth Amendment requires prison officials to "take reasonable measures to guarantee the safety of the inmates." Hudson v. Palmer, 468 U.S. 517, 526-27 (1984). In order to state an Eighth Amendment failure to protect claim, Plaintiff must allege facts sufficient to show that the risk he faced was objectively "sufficiently serious" and that the conditions under which he was confined posed a "substantial risk of serious harm" to him. Farmer, 511 U.S. at 834.