From OCLC: The WorldCat Discovery service will be unavailable from 10 pm (EDT) Saturday, May 20 to 7:00 am (EDT) Sunday, May 21, for maintenance scheduled to upgrade our storage systems. This system maintenance will impact all OCLC services except Hosted EZproxy.
Given the 9 hour anticipated duration of this outage, Steven is going to throw a notice up on our website (even though it’s a super low use time period).