Each flume node is generating Write-Ahead-Log (WAL) in directory specified by "flume.agent.logdir"
Lets say a flume node is running on some production sever and collecting logs generated by the production server to some collector node running on some other server. Then one would like to specify the size of WAL directory. Because no one would like their production server to run out of space when some collector node is down.
Also if one doesn't want to lose his/her log data there should be option for that choice too.
So Requirements can be spelled as follows:
1)One should be able to specify the size of WAL directory and there should be option of "unlimited" size too. This "unlimited" will be helpful for those people who don't want to lose their logs at any cost.
2)If size is specified WAL directory should implement some algorithm regarding
a)Whether one wants the all latest log to be store in the WAL directory
b)OR one wants to stop writing to WAL directory as soon it reaches the size limit