Solid-state disk caching the top-K hard-disk blocks selected as a function of access frequency and a logarithmic system time
US8838895B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 2011 |
| Grant date | Sep 16, 2014 |
| Priority date | — |
| Expiry date | Mar 27, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/7208
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A solid state disk (SSD) caches disk-based volumes in a heterogeneous storage system, improving the overall storage-system performance. The hottest data blocks are identified based on two factors: the frequency of access, and temporal locality. Temporal locality is computed using a logarithmic system time. IO latency is reduced by migrating these hottest data blocks from hard-disk-based volumes to the solid-state flash-memory disks. Some dedicated mapping metadata and a novel top-K B-tree structure are used to index the blocks. Data blocks are ranked by awarding a higher current value for recent accesses, but also by the frequency of accesses. A non-trivial value for accesses in the past is retained by accumulating the two factors over many time spans expressed as a logarithmic system time. Having two factors, access frequency and the logarithmic system time, provides for a more balanced caching system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.