BUDGETING OPEN BLOCKS OF A STORAGE UNIT BASED ON POWER LOSS PREVENTION

A storage unit has one or more processing devices, a solid-state drive and an open blocks cache memory. The open blocks cache memory holds open blocks of data or metadata and holds closed blocks of data or metadata pending writing to the solid-state drive. Closed blocks of data or metadata are written to the solid-state drive and open blocks of data or metadata are written to the open blocks cache memory. Values for open blocks in the open blocks cache memory are tracked. The values are adjusted in a first direction when an open block is written to the open blocks cache memory, and the values are adjusted in a second direction when an open block in the open blocks cache memory is closed and written from the open blocks cache memory to the solid-state drive.