What is the initial burden of persuasion for a motion for failure to exhaust?

In a summary judgment motion for failure to exhaust, the defendant has the initial burden to establish "that there was an available administrative remedy, and that the prisoner did not exhaust that available remedy." Albino v. Baca, 747 F.3d 1162, 1172 (9th Cir. 2014). If the defendant carries that burden, "the burden shifts to the prisoner to come forward with evidence showing that there is something in his particular case that made the existing and generally available administrative remedies effectively unavailable to him." Id. The ultimate burden of persuasion remains with defendant, however. Id.