I have a client using a Seagate Business NAS 16 Terabyte device on his home network. It is being used for file sharing on one Windows 7 computer and two Mac's running osx 10.9. File sharing works great on all computers. Problem is with Time Machine, it is enabled on the NAS as well as AFP. Time Machine backup will sometimes work and others time not, just fails with either a device not detected or delayed message. Both MAC's do this. Not sure where to begin with this one. Everything seems fine other than time machine backup.
Client was running 1.8 a couple weeks ago with the same problem.