There appears to have been a significant performance change in WiredTiger from 6554a50 on the SSL Windows 2008R2 builder. It has inadvertently exposed a latent issue in the design of the backup_restore*.js tests, where the CRUD client is able to perform write operations quickly enough that it causes both the secondary taken offline for the backup and the secondary that remains online to fall off the primary's oplog. We should have the CRUD client periodically use a write concern of w=3 to avoid either of the secondaries from becoming too far behind.