https://www.quora.com/Why-does-flume-take-more-resource-CPU-when-file-channel-is-used-compared-to-when-memory-channel-is-used
In case of File channel , the CPU would be used for the following
- Serializing/Deserializing Events from/to file channel . In memory channel , this is plainly stored in RAM , so no serialization is required.
- A small cpu overhead per disk write in determining the disk location where it needs to write. Typically this will be backed by swap file . So you will not see this per event. But will see CPU spikes when moving from physical to swap.
So this increase is not entirely unexpected. However , you should look closer if this increase in CPU is high enough to slow down the system.