Does Your code solve the evictions problem associated with reboot of the memcached server as You pointed out referring to a blog post here http://dormando.livejournal.com/495593.html . The replies to this blog post, mentioned the possibility of having redundant memcached servers. However, the Moodle documentation implies only using nonredundant configuration.
As a sysadmin for a small university, I am concerned that the students that are kicked out of sessions, would not get a fair chance to complete their tests. Since the file system is a bottleneck in my setup, I will not put the sessions in the file system. Any chance of eviction, however small is unacceptable, so this leaves me with sessions in the database with a memcached offload, preferably redundant. Does Your code support this type of setup? And if so, are there any examples of configuration?