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https://issues.apache.org/jira/browse/FLUME-1227?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13628201#comment-13628201
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Hari Shreedharan commented on FLUME-1227:
-----------------------------------------

Thanks for your patience with this Roshan.
This approach seems fine. It is a good idea to explicitly do the instantiation 
inside the SC. You can go ahead with that for now I guess.

But here is some food for thought - The fundamental difference between this 
channel and the File Channel is the way the transactions get written out. Have 
you considered inheriting the File Channel and then adding a 2nd data structure 
(your primary memory channel) and have the decision making happen in the 
transaction code? I am not sure how feasible it is or even how smart an idea it 
is, but it might be worth considering.
                
> Introduce some sort of SpillableChannel
> ---------------------------------------
>
>                 Key: FLUME-1227
>                 URL: https://issues.apache.org/jira/browse/FLUME-1227
>             Project: Flume
>          Issue Type: New Feature
>          Components: Channel
>            Reporter: Jarek Jarcec Cecho
>            Assignee: Roshan Naik
>         Attachments: 1227.patch.1, SpillableMemory Channel Design.pdf
>
>
> I would like to introduce new channel that would behave similarly as scribe 
> (https://github.com/facebook/scribe). It would be something between memory 
> and file channel. Input events would be saved directly to the memory (only) 
> and would be served from there. In case that the memory would be full, we 
> would outsource the events to file.
> Let me describe the use case behind this request. We have plenty of frontend 
> servers that are generating events. We want to send all events to just 
> limited number of machines from where we would send the data to HDFS (some 
> sort of staging layer). Reason for this second layer is our need to decouple 
> event aggregation and front end code to separate machines. Using memory 
> channel is fully sufficient as we can survive lost of some portion of the 
> events. However in order to sustain maintenance windows or networking issues 
> we would have to end up with a lot of memory assigned to those "staging" 
> machines. Referenced "scribe" is dealing with this problem by implementing 
> following logic - events are saved in memory similarly as our MemoryChannel. 
> However in case that the memory gets full (because of maintenance, networking 
> issues, ...) it will spill data to disk where they will be sitting until 
> everything start working again.
> I would like to introduce channel that would implement similar logic. It's 
> durability guarantees would be same as MemoryChannel - in case that someone 
> would remove power cord, this channel would lose data. Based on the 
> discussion in FLUME-1201, I would propose to have the implementation 
> completely independent on any other channel internal code.
> Jarcec

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