What is the burden of proving plaintiff failed to exhaust available administrative remedies?

Defendants' evidence establishes that plaintiff failed to exhaust available administrative remedies prior to filing suit. Accordingly, the court finds that defendants have satisfied their initial burden of proving plaintiff's failure to exhaust. As discussed below, plaintiff has not responded by demonstrating that he exhausted his administrative remedies, that such administrative remedies were unavailable, or that prison officials effectively obstructed his ability to pursue his grievance through the director's level of review. See Ngo v. Woodford, 539 F.3d 1108, 1110 (9th Cir. 2008).