Most of my queries might be driven due to lack of sufficient context of Tachyon - in which case, please do bear with me :-)

Curious about what happens if an application puts data into tachyon and it is running short of memory : how does it manage it ?
At time of inserting the data and 'later'.

At time of insertion - will it simply fail or try to buffer to disk/etc (upto some limit ofcourse) ?

What about blowing memory limits subsequent to successful addition [due to operations (read/write buffers, etc causing memory requirements to grow) ] : is there a notification to spark in case a previously accept block needs to be dropped ? Or is the gaurantee that once added, it wont be dropped (Dump to disk ? Dump to hdfs ? drop silently ? Is this customizable ?)