| 摘要 |
A sequence of fixed-size blocks defines a page (e.g., in a server system, storage subsystem, DASD, etc.). Each fixed-size block includes a data block and a footer. A high performance block storage metadata unit associated with the page is created from a confluence of the footers. The confluence of footers has space available for application metadata. In an embodiment, the metadata space is utilized to record a “write activity level” metric, and a timestamp. The metric indicates the write frequency or “hotness” of the page, and its value changes over time as the activity level changes. Storage subsystem performance may be enhanced by mapping frequently accessed pages to higher performance physical disks and mapping infrequently accessed pages to lower power physical disks. This approach is advantageous in that the metric is recorded on a non-volatile basis and may be readily communicated between system components (e.g., between a host computer and a storage subsystem).
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