diff --git a/web/src/Top.tsx b/web/src/Top.tsx
index eabe246..c077bf8 100644
--- a/web/src/Top.tsx
+++ b/web/src/Top.tsx
@@ -251,6 +251,19 @@ export default function Top() {
   // the process table, and the CPU model, come from the same place the Processes page reads
   const [pt, setPt] = useState<ProcTable | null>(null)
   const [pickedIf, setPickedIf] = useState<string | null>(null) // which NIC the net box draws
+  // Which pool each drive belongs to, asked once: a drive in a ZFS pool has no filesystem of
+  // its own, and "nothing is on it" would be a lie about eight drives holding a NAS.
+  const [pools, setPools] = useState<Record<string, string>>({})
+  useEffect(() => {
+    let live = true
+    api.storage().then((r) => {
+      if (!live) return
+      const m: Record<string, string> = {}
+      for (const d of r.devices) for (const part of d.parts) if (part.fstype === 'zfs_member' && part.label) m[d.name] = part.label
+      setPools(m)
+    }).catch(() => { /* the rows simply say less */ })
+    return () => { live = false }
+  }, [])
   const [err, setErr] = useState('')
   useEffect(() => {
     let stop = false
@@ -389,7 +402,7 @@ export default function Top() {
             // shows what is true of the hardware — how busy it is, and how hot.
             const on = fs.filter((f) => f.disk === d.name)
             const used = on.reduce((a, f) => a + f.used, 0)
-            return <Disk key={d.name} name={d.name} note={d.model} size={d.size} used={on.length ? used : undefined} io={d.util_pct} temp={d.temp} mounts={on.map((f) => f.mount)} />
+            return <Disk key={d.name} name={d.name} note={d.model} size={d.size} used={on.length ? used : undefined} io={d.util_pct} temp={d.temp} mounts={on.map((f) => f.mount)} pool={pools[d.name]} />
           })}
           {(s?.disks ?? []).length === 0 && <div className="t-dim">no drives reported</div>}
         </div>
@@ -485,7 +498,7 @@ const Rows = memo(function Rows({ procs, sel, onSel, curves, empty }: { procs: P
 
 // One physical drive. `used` is the bytes of the filesystems on it, left out when none can
 // be attributed to it — a pool member's share of a pool is not a number worth inventing.
-function Disk({ name, note, size, used, io, temp, mounts }: { name: string; note?: string; size: number; used?: number; io?: number; temp?: number; mounts?: string[] }) {
+function Disk({ name, note, size, used, io, temp, mounts, pool }: { name: string; note?: string; size: number; used?: number; io?: number; temp?: number; mounts?: string[]; pool?: string }) {
   const upct = used !== undefined && size > 0 ? (used / size) * 100 : 0
   return (
     <div className="t-disk">
@@ -504,7 +517,7 @@ function Disk({ name, note, size, used, io, temp, mounts }: { name: string; note
           {mounts && mounts.length > 0 && <div className="t-row t-sub t-dim t-mounts" title={mounts.join('  ')}>{mounts.join(' ')}</div>}
         </>
       ) : (
-        <div className="t-row t-sub t-dim">no filesystem of this machine is on it</div>
+        <div className="t-row t-sub t-dim">{pool ? `member of ZFS pool ${pool}` : 'nothing mounted from it'}</div>
       )}
     </div>
   )