diff --git a/lib/propolis/src/block/crucible.rs b/lib/propolis/src/block/crucible.rs
index 4adc085dd..f0cfdb26e 100644
--- a/lib/propolis/src/block/crucible.rs
+++ b/lib/propolis/src/block/crucible.rs
@@ -168,7 +168,10 @@ impl CrucibleBackend {
             .map_err(|e| io::Error::from(CrucibleError::from(e)))?;
 
         // Decide if we need to scrub this volume or not.
-        if volume.has_read_only_parent() {
+        //
+        // We should not scrub read-only volumes, as we cannot write back to
+        // them, due to...you know, being read-only. So just don't do that.
+        if !opts.is_read_only() && volume.has_read_only_parent() {
             let vclone = volume.clone();
             tokio::spawn(async move {
                 let volume_id = vclone.get_uuid().await.unwrap();
@@ -217,7 +220,7 @@ impl CrucibleBackend {
         let info = block::DeviceInfo {
             block_size: block_size as u32,
             total_size: sectors,
-            read_only: opts.read_only.unwrap_or(false),
+            read_only: opts.is_read_only(),
             supports_discard: false,
         };
 
diff --git a/lib/propolis/src/block/mod.rs b/lib/propolis/src/block/mod.rs
index 5d79c0119..ccc183f8b 100644
--- a/lib/propolis/src/block/mod.rs
+++ b/lib/propolis/src/block/mod.rs
@@ -275,6 +275,13 @@ pub struct BackendOpts {
     pub skip_flush: Option<bool>,
 }
 
+impl BackendOpts {
+    /// Return `true` if and only if this backend is configured to be read-only.
+    pub fn is_read_only(&self) -> bool {
+        self.read_only.unwrap_or(false)
+    }
+}
+
 /// Top-level trait for block devices (frontends) to translate guest block IO
 /// requests into [Request]s for the attached [Backend]
 pub trait Device: Send + Sync + 'static {