libnss-cache is a NSS module for reading directory service information for Linux hosts from an indexed, local disk cache of that directory service.
It is paired with https://github.com/google/nsscache, a tool that asynchronously synchronises the local NSS database with remote directory services.
Mailing list: https://groups.google.com/forum/#!forum/nsscache-discuss
Issue history is at https://code.google.com/p/nsscache/issues/list