This object records the largest single read operation's block count seen so far on this LUN/flow, a high-water mark rather than a cumulative total. An admin profiling an application's I/O pattern on this path uses this figure to understand the peak read-request size the host has issued, which matters for tuning buffer or acceleration settings on that flow. A max of 2,048 blocks (roughly 1 MB at 512 bytes/block) would indicate the host occasionally issues large sequential read requests even if most reads are much smaller.