diff --git a/ciao-controller/instance.go b/ciao-controller/instance.go
index 5e6369abf..2ccd46781 100644
--- a/ciao-controller/instance.go
+++ b/ciao-controller/instance.go
@@ -169,7 +169,6 @@ func addBlockDevice(c *controller, tenant string, instanceID string, device stor
 	// a block device is bootable.
 	data := types.BlockData{
 		BlockDevice: device,
-		Size:        s.Size,
 		CreateTime:  time.Now(),
 		TenantID:    tenant,
 		Name:        fmt.Sprintf("Storage for instance: %s", instanceID),
diff --git a/ciao-controller/internal/datastore/datastore_test.go b/ciao-controller/internal/datastore/datastore_test.go
index 14702db01..f10e366f5 100644
--- a/ciao-controller/internal/datastore/datastore_test.go
+++ b/ciao-controller/internal/datastore/datastore_test.go
@@ -1346,7 +1346,6 @@ func TestAttachVolumeFailure(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    newTenant.ID,
 		CreateTime:  time.Now(),
@@ -1403,7 +1402,6 @@ func TestDetachVolumeFailure(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    newTenant.ID,
 		CreateTime:  time.Now(),
@@ -1495,7 +1493,6 @@ func TestAddBlockDevice(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    newTenant.ID,
 		CreateTime:  time.Now(),
@@ -1537,7 +1534,6 @@ func TestDeleteBlockDevice(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    newTenant.ID,
 		CreateTime:  time.Now(),
@@ -1585,7 +1581,6 @@ func TestUpdateBlockDevice(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    newTenant.ID,
 		CreateTime:  time.Now(),
@@ -1649,7 +1644,6 @@ func TestUpdateBlockDeviceErr(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    newTenant.ID,
 		CreateTime:  time.Now(),
@@ -1674,7 +1668,6 @@ func TestCreateStorageAttachment(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -1736,7 +1729,6 @@ func TestUpdateStorageAttachmentExisting(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -1804,7 +1796,6 @@ func TestUpdateStorageAttachmentNotExisting(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -1848,7 +1839,6 @@ func TestUpdateStorageAttachmentDeleted(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -1903,7 +1893,6 @@ func TestGetStorageAttachment(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -1960,7 +1949,6 @@ func TestGetStorageAttachmentError(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -2003,7 +1991,6 @@ func TestDeleteStorageAttachment(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -2070,7 +2057,6 @@ func TestDeleteStorageAttachmentError(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
@@ -2142,7 +2128,6 @@ func TestGetVolumeAttachments(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenant.ID,
 		CreateTime:  time.Now(),
diff --git a/ciao-controller/internal/datastore/sqlite3db_test.go b/ciao-controller/internal/datastore/sqlite3db_test.go
index 875556c23..be64a1389 100644
--- a/ciao-controller/internal/datastore/sqlite3db_test.go
+++ b/ciao-controller/internal/datastore/sqlite3db_test.go
@@ -68,7 +68,6 @@ func TestSQLiteDBGetTenantDevices(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    uuid.Generate().String(),
 		CreateTime:  time.Now(),
@@ -114,7 +113,6 @@ func TestSQLiteDBGetTenantWithStorage(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    tenantID,
 		CreateTime:  time.Now(),
@@ -155,7 +153,6 @@ func TestSQLiteDBGetAllBlockData(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    uuid.Generate().String(),
 		CreateTime:  time.Now(),
@@ -191,7 +188,6 @@ func TestSQLiteDBDeleteBlockData(t *testing.T) {
 
 	data := types.BlockData{
 		BlockDevice: blockDevice,
-		Size:        0,
 		State:       types.Available,
 		TenantID:    uuid.Generate().String(),
 		CreateTime:  time.Now(),
diff --git a/ciao-controller/openstack_volume.go b/ciao-controller/openstack_volume.go
index b2bbe865f..6150fe447 100644
--- a/ciao-controller/openstack_volume.go
+++ b/ciao-controller/openstack_volume.go
@@ -71,7 +71,6 @@ func (c *controller) CreateVolume(tenant string, req block.RequestedVolume) (blo
 	// you should modify BlockData to include a "bootable" flag.
 	data := types.BlockData{
 		BlockDevice: bd,
-		Size:        req.Size,
 		CreateTime:  time.Now(),
 		TenantID:    tenant,
 		State:       types.Available,
diff --git a/ciao-controller/types/types.go b/ciao-controller/types/types.go
index 7b666d974..d9a8f3c38 100644
--- a/ciao-controller/types/types.go
+++ b/ciao-controller/types/types.go
@@ -258,7 +258,6 @@ const (
 type BlockData struct {
 	storage.BlockDevice
 	TenantID    string     // the tenant who owns this volume
-	Size        int        // size in GB
 	State       BlockState // status of
 	CreateTime  time.Time  // when we created the volume
 	Name        string     // a human readable name for this volume
diff --git a/ciao-storage/block.go b/ciao-storage/block.go
index ca6edf4f6..0534702c1 100644
--- a/ciao-storage/block.go
+++ b/ciao-storage/block.go
@@ -47,5 +47,5 @@ type BlockDevice struct {
 	Local     bool   // local (ephemeral) or volume service backed
 	Swap      bool   // linux swap device (attempt swapon via cloudinit)
 	Tag       string // arbitrary text identifier
-	Size      int    // gigabyte size for autocreation
+	Size      int    // size in GiB
 }
diff --git a/ciao-storage/ceph.go b/ciao-storage/ceph.go
index d69b49307..6f70d29a9 100644
--- a/ciao-storage/ceph.go
+++ b/ciao-storage/ceph.go
@@ -32,6 +32,22 @@ type CephDriver struct {
 	ID string
 }
 
+func (d CephDriver) getBlockDeviceSizeGiB(volumeUUID string) (int, error) {
+	bytes, err := d.GetBlockDeviceSize(volumeUUID)
+
+	if err != nil {
+		return 0, err
+	}
+
+	// When converting to GiB round up unless we've got a multiple of 1GiB
+	res := bytes / (1024 * 1024 * 1024)
+	rem := bytes % (1024 * 1024 * 1024)
+	if rem == 0 {
+		return int(res), nil
+	}
+	return int(res + 1), nil
+}
+
 // CreateBlockDevice will create a rbd image in the ceph cluster.
 func (d CephDriver) CreateBlockDevice(volumeUUID string, imagePath string, size int) (BlockDevice, error) {
 	if volumeUUID == "" {
@@ -61,7 +77,7 @@ func (d CephDriver) CreateBlockDevice(volumeUUID string, imagePath string, size
 		return BlockDevice{}, fmt.Errorf("Error when running: %v: %v: %s", cmd.Args, err, out)
 	}
 
-	return BlockDevice{ID: volumeUUID}, nil
+	return BlockDevice{ID: volumeUUID, Size: size}, nil
 }
 
 // CreateBlockDeviceFromSnapshot will create a block device derived from the previously created snapshot.
@@ -77,7 +93,13 @@ func (d CephDriver) CreateBlockDeviceFromSnapshot(volumeUUID string, snapshotID
 		return BlockDevice{}, fmt.Errorf("Error when running: %v: %v: %s", cmd.Args, err, out)
 	}
 
-	return BlockDevice{ID: ID}, nil
+	size, err := d.getBlockDeviceSizeGiB(volumeUUID)
+	if err != nil {
+		d.DeleteBlockDevice(volumeUUID)
+		return BlockDevice{}, fmt.Errorf("Error when querying block device size: %v", err)
+	}
+
+	return BlockDevice{ID: ID, Size: size}, nil
 }
 
 // CreateBlockDeviceSnapshot creates and protects the snapshot with the provided name
@@ -113,7 +135,13 @@ func (d CephDriver) CopyBlockDevice(volumeUUID string) (BlockDevice, error) {
 		return BlockDevice{}, fmt.Errorf("Error when running: %v: %v: %s", cmd.Args, err, out)
 	}
 
-	return BlockDevice{ID: ID}, nil
+	size, err := d.getBlockDeviceSizeGiB(volumeUUID)
+	if err != nil {
+		d.DeleteBlockDevice(volumeUUID)
+		return BlockDevice{}, fmt.Errorf("Error when querying block device size: %v", err)
+	}
+
+	return BlockDevice{ID: ID, Size: size}, nil
 }
 
 // DeleteBlockDevice will remove a rbd image from the ceph cluster.
diff --git a/ciao-storage/noop.go b/ciao-storage/noop.go
index 9098c71bf..02a0f9fb4 100644
--- a/ciao-storage/noop.go
+++ b/ciao-storage/noop.go
@@ -29,7 +29,7 @@ type NoopDriver struct {
 
 // CreateBlockDevice pretends to create a block device.
 func (d *NoopDriver) CreateBlockDevice(volumeUUID string, image string, size int) (BlockDevice, error) {
-	return BlockDevice{ID: uuid.Generate().String()}, nil
+	return BlockDevice{ID: uuid.Generate().String(), Size: size}, nil
 }
 
 // CreateBlockDeviceFromSnapshot pretends to create a block device snapshot