hesela.devSMaRT (SMR translation)
SMaRT is a research SMR translation scheme that combines in-place track updates with relocation and free-space consolidation.
A free following track permits an in-place update. Otherwise SMaRT relocates the updated track and changes its track-level mapping. Garbage collection joins fragmented free regions by moving live tracks, while allocation and migration gradually separate frequently updated data. [1]
DiskSim experiments used four write-intensive traces with scaled and modulo-trimmed addresses at 30%, 60% and 90% utilization. The low- and medium-utilization advantage over the modeled cache-based comparator narrowed at 90%. These are simulated configurations, not drive-wide operating thresholds. [1]
The paper's amplified-write percentage counts write requests triggering foreground GC, not physical bytes divided by host bytes. Its GC-overhead plots also mix migrated tracks for SMaRT with I/O-request counts for the comparator. [1]
Relations
Limitations
- Mapping recovery is sketched using persistent checkpoints and per-track backpointers; the performance evaluation does not establish power-loss correctness. [1]
Citations
Sources & caveats
- Full FAST 2017 paper reviewed, especially sections 4.5 and 5.1-5.5. No benchmark or power-loss experiment was reproduced.
- The DiskSim model used a 146 GB drive geometry at 512-byte sectors. Address transformations, prepopulation and utilization are part of the experiment.
- Section 5.5.4 explicitly states that the two GC-overhead units are not directly comparable despite sharing an axis.