# facebookarchive/flashcache

A general purpose, write-back block cache for Linux.

Repository: https://github.com/facebookarchive/flashcache
Canonical: https://ross.abutalabs.com/products/flashcache
Language: C
License: GPL-2.0
License Family: copyleft
Archived: true
Last push: 2021-10-13T07:34:21+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 6009, "days_push": 1785, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1601, forks 410 (observed 2026-08-28T04:05:09.604101+00:00)

## What it is
Flashcache is a Linux kernel module (device-mapper target) that provides a general-purpose write-back block cache, using an SSD to cache reads and writes for slower block devices. It was originally developed at Facebook and is now archived and unmaintained.

## Use cases
- speed up disk-backed databases with an SSD write-back cache
- cache a slow spinning disk with an SSD on Linux
- reduce write latency for MySQL or other storage workloads
- create a device-mapper cached block volume
- add a write-through SSD cache layer for block devices

## When to choose
- you must maintain a legacy Linux 2.6-era system already using flashcache
- you need a GPL-2.0 write-back block cache and accept unmaintained code

## When to avoid
- you need actively maintained software
- you run modern kernels (use bcache, lvmcache, or dm-cache instead)
- you need filesystem-level or distributed caching rather than block-level

## Facets
- artifact type: library
- maturity: abandoned
- function: caching, file-system
- domain: databases, performance, operating-systems
- platform: c
- tags: block-cache, write-back, kernel-module, dm-target, ssd-cache, archived, linux

## Member repositories
- facebookarchive/flashcache (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:09.604101+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:52:47.749122+00:00, confidence not recorded.
  - readme: https://github.com/facebookarchive/flashcache (fetched 2026-08-28T04:05:09.604101+00:00, sha accafd1e73f5)
- Data as of 2026-08-30T08:39:29.467469+00:00.