diff --git a/src/sftp.js b/src/sftp.js
index 5687da2ab..f1ffb9128 100644
--- a/src/sftp.js
+++ b/src/sftp.js
@@ -11,7 +11,8 @@ var apps = require('./apps.js'),
     debug = require('debug')('box:sftp'),
     infra = require('./infra_version.js'),
     safe = require('safetydance'),
-    shell = require('./shell.js');
+    shell = require('./shell.js'),
+    _ = require('underscore');
 
 function startSftp(existingInfra, callback) {
     assert.strictEqual(typeof existingInfra, 'object');
@@ -60,31 +61,49 @@ function rebuild(callback) {
             dataDirs.push({ hostDir, mountDir });
         });
 
-        const appDataVolumes = dataDirs.map(function (v) { return `-v "${v.hostDir}:${v.mountDir}"`; }).join(' ');
 
-        const cmd = `docker run --restart=always -d --name="sftp" \
-                    --hostname sftp \
-                    --net cloudron \
-                    --net-alias sftp \
-                    --log-driver syslog \
-                    --log-opt syslog-address=udp://127.0.0.1:2514 \
-                    --log-opt syslog-format=rfc5424 \
-                    --log-opt tag=sftp \
-                    -m ${memoryLimit}m \
-                    --memory-swap ${memoryLimit * 2}m \
-                    --dns 172.18.0.1 \
-                    --dns-search=. \
-                    -p 222:22 \
-                    ${appDataVolumes} \
-                    -v "/etc/ssh:/etc/ssh:ro" \
-                    --label isCloudronManaged=true \
-                    --read-only -v /tmp -v /run "${tag}"`;
+        shell.exec('inspectSftp', 'docker inspect --format="{{json .Mounts }}" sftp', function (error, result) {
+            if (!error && result) {
+                let currentDataDirs = safe.JSON.parse(result);
+                if (currentDataDirs) {
+                    currentDataDirs = currentDataDirs.filter(function (d) { return d.Destination.indexOf('/app/data/') === 0; }).map(function (d) { return { hostDir: d.Source, mountDir: d.Destination }; });
 
-        // ignore error if container not found (and fail later) so that this code works across restarts
-        async.series([
-            shell.exec.bind(null, 'stopSftp', 'docker stop sftp || true'),
-            shell.exec.bind(null, 'removeSftp', 'docker rm -f sftp || true'),
-            shell.exec.bind(null, 'startSftp', cmd)
-        ], done);
+                    // sort for comparison
+                    currentDataDirs.sort(function (a, b) { return a.hostDir < b.hostDir ? -1 : 1; });
+                    dataDirs.sort(function (a, b) { return a.hostDir < b.hostDir ? -1 : 1; });
+
+                    if (_.isEqual(currentDataDirs, dataDirs)) {
+                        debug('Skipping rebuild, no changes');
+                        return done();
+                    }
+                }
+            }
+
+            const appDataVolumes = dataDirs.map(function (v) { return `-v "${v.hostDir}:${v.mountDir}"`; }).join(' ');
+            const cmd = `docker run --restart=always -d --name="sftp" \
+                        --hostname sftp \
+                        --net cloudron \
+                        --net-alias sftp \
+                        --log-driver syslog \
+                        --log-opt syslog-address=udp://127.0.0.1:2514 \
+                        --log-opt syslog-format=rfc5424 \
+                        --log-opt tag=sftp \
+                        -m ${memoryLimit}m \
+                        --memory-swap ${memoryLimit * 2}m \
+                        --dns 172.18.0.1 \
+                        --dns-search=. \
+                        -p 222:22 \
+                        ${appDataVolumes} \
+                        -v "/etc/ssh:/etc/ssh:ro" \
+                        --label isCloudronManaged=true \
+                        --read-only -v /tmp -v /run "${tag}"`;
+
+            // ignore error if container not found (and fail later) so that this code works across restarts
+            async.series([
+                shell.exec.bind(null, 'stopSftp', 'docker stop sftp || true'),
+                shell.exec.bind(null, 'removeSftp', 'docker rm -f sftp || true'),
+                shell.exec.bind(null, 'startSftp', cmd)
+            ], done);
+        });
     });
 }
diff --git a/src/shell.js b/src/shell.js
index 20d1588e8..a57e9fc95 100644
--- a/src/shell.js
+++ b/src/shell.js
@@ -23,10 +23,12 @@ function exec(tag, cmd, callback) {
     debug(`${tag} exec: ${cmd}`);
 
     child_process.exec(cmd, function (error, stdout, stderr) {
-        debug(`${tag} (stdout): %s`, stdout.toString('utf8'));
+        const stdoutResult = stdout.toString('utf8');
+
+        debug(`${tag} (stdout): %s`, stdoutResult);
         debug(`${tag} (stderr): %s`, stderr.toString('utf8'));
 
-        callback(error);
+        callback(error, stdoutResult);
     });
 }