ZFS tab: Writes — the RAM write buffer, each pool's write rate, and a landing tier with its mover

Live from arcstats (dirty), dmu_tx (throttled writes), each pool's txgs (bytes synced to disk)
and objset kstats (bytes from programs). A landing tier — a mergerfs pool whose first branch is
fast storage and whose last is a ZFS dataset — is detected from mergerfs's branch xattr; a mover
status file in /run/landing-mover/ adds its queue, the file in flight and totals. Sensors
zfs.write.*, zfs.<pool>.write_bps|logical_bps and zfs.<pool>.landing.* carry the history.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/styles.css

@@ -884,6 +884,8 @@ pre.diff .add { color: var(--ok); background: color-mix(in srgb, var(--ok) 12%,
 .arc-tier { display: flex; gap: 8px; min-width: 0; } .arc-tier .k { color: var(--muted); width: 80px; flex-shrink: 0; cursor: help; }
 .arc-tier-v { display: flex; flex-direction: column; gap: 1px; min-width: 0; } .arc-tier-v > span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
 .arc-tier-v .none { color: var(--muted); white-space: normal; }
+.landing-tier { border: 1px solid var(--border); border-radius: 8px; padding: 8px 10px; margin: 4px 0 6px; font-size: 13px; }
+.landing-tier .props .badge { margin-right: 2px; }
 
 /* ---- Space: what is using a disk ---- */
 .space { position: absolute; inset: 0; display: flex; flex-direction: column; background: var(--bg); min-height: 0; }