diff --git a/collector/physical_disk.go b/collector/physical_disk.go
new file mode 100644
index 0000000..59b8078
--- /dev/null
+++ b/collector/physical_disk.go
@@ -0,0 +1,157 @@
+package collector
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"sync"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+func init() {
+	registerCollector("physical_disk", func(logger *slog.Logger) Collector {
+		return newPhysicalDiskCollector(logger)
+	})
+}
+
+type physicalDiskCollector struct {
+	logger *slog.Logger
+	mu     sync.Mutex
+	nodes  []string
+}
+
+func newPhysicalDiskCollector(logger *slog.Logger) *physicalDiskCollector {
+	return &physicalDiskCollector{logger: logger}
+}
+
+func (c *physicalDiskCollector) SetNodes(nodes []string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.nodes = nodes
+}
+
+type diskListResponse struct {
+	Data []diskEntry `json:"data"`
+}
+
+type diskEntry struct {
+	DevPath string          `json:"devpath"`
+	Health  string          `json:"health"`
+	Wearout json.RawMessage `json:"wearout"`
+	Size    float64         `json:"size"`
+	Model   string          `json:"model"`
+	Serial  string          `json:"serial"`
+	Type    string          `json:"type"`
+	Used    string          `json:"used"`
+	OSDList []string        `json:"osdid-list"`
+}
+
+var (
+	physDiskHealthDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "physical_disk", "health"),
+		"1 if SMART health is PASSED, 0 otherwise.",
+		[]string{"node", "devpath", "model", "serial", "type"}, nil,
+	)
+	physDiskWearoutDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "physical_disk", "wearout_remaining_ratio"),
+		"Wearout remaining as a ratio (1.0 = new).",
+		[]string{"node", "devpath"}, nil,
+	)
+	physDiskSizeDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "physical_disk", "size_bytes"),
+		"Physical disk size in bytes.",
+		[]string{"node", "devpath"}, nil,
+	)
+	physDiskInfoDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "physical_disk", "info"),
+		"Physical disk information.",
+		[]string{"node", "devpath", "model", "serial", "type", "used"}, nil,
+	)
+	physDiskOSDDesc = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "physical_disk", "osd"),
+		"Disk-to-OSD mapping.",
+		[]string{"node", "devpath", "osd"}, nil,
+	)
+)
+
+func (c *physicalDiskCollector) Update(client *Client, ch chan<- prometheus.Metric) error {
+	c.mu.Lock()
+	nodes := make([]string, len(c.nodes))
+	copy(nodes, c.nodes)
+	c.mu.Unlock()
+
+	var (
+		wg   sync.WaitGroup
+		errs []error
+		emu  sync.Mutex
+	)
+
+	sem := make(chan struct{}, client.MaxConcurrent())
+
+	for _, node := range nodes {
+		wg.Add(1)
+		go func(node string) {
+			defer wg.Done()
+			sem <- struct{}{}
+			defer func() { <-sem }()
+
+			if err := c.collectNode(client, ch, node); err != nil {
+				emu.Lock()
+				errs = append(errs, err)
+				emu.Unlock()
+			}
+		}(node)
+	}
+	wg.Wait()
+
+	if len(errs) > 0 {
+		return fmt.Errorf("physical_disk collection errors: %v", errs)
+	}
+	return nil
+}
+
+func (c *physicalDiskCollector) collectNode(client *Client, ch chan<- prometheus.Metric, node string) error {
+	body, err := client.Get(fmt.Sprintf("/nodes/%s/disks/list", node))
+	if err != nil {
+		return fmt.Errorf("failed to get disks for node %s: %w", node, err)
+	}
+
+	var resp diskListResponse
+	if err := json.Unmarshal(body, &resp); err != nil {
+		return fmt.Errorf("failed to parse disks response for node %s: %w", node, err)
+	}
+
+	for _, disk := range resp.Data {
+		// Health: 1 if PASSED, 0 otherwise.
+		var health float64
+		if disk.Health == "PASSED" {
+			health = 1
+		}
+		ch <- prometheus.MustNewConstMetric(physDiskHealthDesc, prometheus.GaugeValue, health,
+			node, disk.DevPath, disk.Model, disk.Serial, disk.Type)
+
+		// Wearout: try to parse as number. Skip if "N/A" or not a number.
+		if len(disk.Wearout) > 0 {
+			var wearout float64
+			if err := json.Unmarshal(disk.Wearout, &wearout); err == nil {
+				ch <- prometheus.MustNewConstMetric(physDiskWearoutDesc, prometheus.GaugeValue, wearout/100, node, disk.DevPath)
+			}
+		}
+
+		// Size.
+		ch <- prometheus.MustNewConstMetric(physDiskSizeDesc, prometheus.GaugeValue, disk.Size, node, disk.DevPath)
+
+		// Info.
+		ch <- prometheus.MustNewConstMetric(physDiskInfoDesc, prometheus.GaugeValue, 1,
+			node, disk.DevPath, disk.Model, disk.Serial, disk.Type, disk.Used)
+
+		// OSD mapping.
+		for _, osdID := range disk.OSDList {
+			osd := fmt.Sprintf("osd.%s", osdID)
+			ch <- prometheus.MustNewConstMetric(physDiskOSDDesc, prometheus.GaugeValue, 1, node, disk.DevPath, osd)
+		}
+	}
+
+	return nil
+}