annual-replacement-rate · shipping · also ARR

Annual replacement rate

Annual replacement rate (ARR) counts recorded device replacements relative to device exposure, scaled to one year.

For exposure E in drive-years and R recorded replacements, 100 R/E expresses replacements per 100 drive-years. Declare the replacement policy: a replacement record does not certify a physical failure. Do not substitute an end-of-period headcount for exposure when the fleet changes.

Relations

related

afr, drive-day, interarrival-time, mtbf

Citations

1. Schroeder and Gibson, FAST 2007: Disk failures in the real world, sections 2.1-2.3 (accessed 2026-10-12)
2. Hesela: Disk replacement rates are not disk lifetimes (accessed 2026-10-12)

JSON: /data/terms/annual-replacement-rate.json