Allocation of physically-contiguous memory buffers is required by many device drivers, but it cannot always be reliably done on long-running Linux systems. That leads to all kinds of unsatisfying ...

Lets say you setup thin-provisioning on a LUN (LUN A) and initially it's sized to 100GB but only uses 10GB (assume the data is being written in a contiguous matter), then another LUN (LUN B) is ...

Indeed, that's just what the lumpy reclaim and memory compaction features do. They've helped, but it's still hard to reliably provide physically contiguous buffers in the megabyte size range, ...