But that (monitoring in almost real time and not looking at accumulative values) is the only way it works. You're not interested in amount written at the filesystem or block device layer but at the flash layer below. Since that's the only layer that matters here and due to the nature of flash storage a lot is different here compared to spinning rust (HDDs). We're back at 'write amplification' again: https://en.wikipedia.org/wiki/Write_amplification   Overwriting one byte physically on