This object records the largest single write operation's block count observed on this LUN/flow, a high-water mark rather than a running total. An admin profiling application behavior on this path uses this to understand the biggest write burst the host has issued, informing decisions about buffer sizing for write-acceleration on that flow. A spike to 4,096 blocks (about 2 MB) during a nightly batch job, versus a normal pattern of small writes the rest of the day, would show up clearly in this peak figure.