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Sharp Checkpointing has side-effects when throughput of data updates is greater than throughput of physical storage device. Under heavy load of writes, operations per second rate periodically drops to zero:

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When offheap memory accumulates too many dirty pages (pages with data not written to disk yet), Ignite node initiates checkpoint — process of writing сonsistent snapshot of all pages to disk storage. If dirty page is changed during ongoing checkpoint before being written to disk, its previous state is copied to a special data region — checkpoint buffer:

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Slow storage devices cause long-running checkpoints. And if load is high while checkpoint is slow, two bad things can happen:

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