diff --git a/control_plane/src/etcd.rs b/control_plane/src/etcd.rs
index df657dd1be..bc39b7dea3 100644
--- a/control_plane/src/etcd.rs
+++ b/control_plane/src/etcd.rs
@@ -48,6 +48,10 @@ pub fn start_etcd_process(env: &local_env::LocalEnv) -> anyhow::Result<()> {
             format!("--data-dir={}", etcd_data_dir.display()),
             format!("--listen-client-urls={client_urls}"),
             format!("--advertise-client-urls={client_urls}"),
+            // Set --quota-backend-bytes to keep the etcd virtual memory
+            // size smaller. Our test etcd clusters are very small.
+            // See https://github.com/etcd-io/etcd/issues/7910
+            "--quota-backend-bytes=100000000".to_string(),
         ])
         .stdout(Stdio::from(etcd_stdout_file))
         .stderr(Stdio::from(etcd_stderr_file))
diff --git a/test_runner/fixtures/zenith_fixtures.py b/test_runner/fixtures/zenith_fixtures.py
index 8f9bf1c11b..7f5b2ad2aa 100644
--- a/test_runner/fixtures/zenith_fixtures.py
+++ b/test_runner/fixtures/zenith_fixtures.py
@@ -1893,7 +1893,11 @@ class Etcd:
                 f"--data-dir={self.datadir}",
                 f"--listen-client-urls={client_url}",
                 f"--advertise-client-urls={client_url}",
-                f"--listen-peer-urls=http://127.0.0.1:{self.peer_port}"
+                f"--listen-peer-urls=http://127.0.0.1:{self.peer_port}",
+                # Set --quota-backend-bytes to keep the etcd virtual memory
+                # size smaller. Our test etcd clusters are very small.
+                # See https://github.com/etcd-io/etcd/issues/7910
+                f"--quota-backend-bytes=100000000"
             ]
             self.handle = subprocess.Popen(args, stdout=log_file, stderr=log_file)