DiskWatch

Single-host disk diagnostics in your terminal. The terminal you open when the disk light won't stop blinking — before you reach for iostat, iotop, smartctl, lsblk, df, du, and a panic.

Sibling to NetWatch and SysWatch. Same chrome. Same palette. Eight tabs covering every disk on one box.

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What it shows

#	Tab	Replaces
1	Overview	one screen across capacity, IO, health, hot files
2	Devices	lsblk, nvme list, diskutil list, hdparm -I
3	Volumes	lvs + vgs, mdadm --detail, diskutil apfs list
4	FS	df -h, df -i, mount, findmnt
5	IO	iostat -x 1, biolatency-style averages
6	SMART	smartctl -A, nvme smart-log
7	Hot Files	fanotify/fseventsd watcher (paths, not bytes)
8	Insights	plain-English anomaly summaries

Where lsblk shows you which disks exist, DiskWatch shows you what's happening on them — capacity trending, IO throughput, p99 latency, SMART health, and the files being written right now — and tells you why in plain English when something's anomalous.

Install

git clone https://github.com/matthart1983/diskwatch.git && cd diskwatch
cargo build --release
./target/release/diskwatch

Or from crates.io:

cargo install diskwatch

Prerequisites: Rust 1.75+. No system dependencies on Linux. macOS calls the standard ioreg, diskutil, and system_profiler binaries — all preinstalled. Optional: smartmontools (brew install smartmontools / apt install smartmontools) for full SMART attribute tables — without it, the SMART tab falls back to the basic verified/failing flag from diskutil.

Keys

Key	Action
1–8	Switch tabs
↑ / ↓ / j / k	Move selection (Devices, FS)
p	Pause / resume sampling
q / Esc	Quit
--diag	Print collected state and exit (no TUI)

Tabs in detail

[1] Overview — 5 KPI tiles (capacity, IO, p99 latency, health, insights), per-device summary, aggregate IO sparkline, top insights, segmented capacity bar.

[2] Devices — block-device table with model, firmware, serial, used %, SMART status. Detail panel for the selected device.

[3] Volumes — APFS containers (macOS) with nested volumes, role, mount, FileVault. mdraid arrays (Linux) with members, slot state [UUUU], resync/recovery progress.

[4] FS — mounted filesystems with inline usage bars, threshold colors, system/user/removable classification.

[5] IO — per-device read / write throughput, 48s sparkline, p50 + p99 latency (read and write) over a 60s rolling window.

[6] SMART — full NVMe / ATA attribute tables when smartctl is on PATH; degraded banner with install instructions when not. Always shows the basic verified/failing flag.

[7] Hot Files — paths by event rate via FSEvents (macOS) / inotify (Linux). Honest footer: this tab can't show bytes/sec or process attribution without root (fs_usage) / Endpoint Security entitlement / eBPF biosnoop.

[8] Insights — anomaly cards over the collected state: capacity warnings, SMART failures, NVMe wear, drive temperature, p99 latency outliers, IO-dominant devices, hot-file runaway, removable drives.

What's real, what's deferred

Metric	macOS	Linux
Device model / serial / firmware	✅ system_profiler + IOKit	✅ /sys/block/*/device/{model,serial,firmware_rev}
Per-device used bytes	✅ via APFS container map	✅ summed from sysinfo mounts
Read/write byte rates (split)	✅ IOKit Statistics	✅ /proc/diskstats cols 5/9
Avg per-op latency	✅ Total Time / Operations	✅ /proc/diskstats cols 6/10
p50 / p99 latency	✅ tick-averaged over 60s	✅ tick-averaged over 60s
True per-op p99 (histogram)	❌ needs IOReport entitlement	❌ needs eBPF biolatency (CAP_BPF)
SMART attributes	✅ smartctl if installed	✅ smartctl if installed
Volumes — APFS	✅ diskutil apfs list	n/a
Volumes — mdraid	n/a	✅ /proc/mdstat
Volumes — ZFS, LVM	⏳ deferred	⏳ deferred
Hot files (paths)	✅ FSEvents	✅ inotify
Hot files — bytes / pid	❌ needs root fs_usage / entitlement	❌ needs eBPF biosnoop

Design

Inherits the *Watch family chrome — #0c1418 background, terminal-green accent, JetBrains Mono, 130×36 character grid with responsive reflow ≥ 110×30. The same character-grid mockups that drive NetWatch and SysWatch drive DiskWatch.

Anti-goals

• Not multi-host. Use NetWatch Cloud if you need a fleet view.
• Not a daemon. No long-running collector, no persisted DB.
• Not a deduper / cleaner. We surface what's eating disk; we don't delete anything. Mutation is a different tool.
• Not a backup product. Snapshots are observed, not authored.
• Not a benchmark. We measure what's happening, not what's possible.

License

MIT.