diff --git a/dashboard/src/components/BackupDialog.vue b/dashboard/src/components/BackupDialog.vue
index f9e6729fd..d827646e3 100644
--- a/dashboard/src/components/BackupDialog.vue
+++ b/dashboard/src/components/BackupDialog.vue
@@ -1,6 +1,6 @@
 <script setup>
 
-import { ref, useTemplateRef, onMounted, computed } from 'vue';
+import { ref, useTemplateRef, onMounted, computed, watch } from 'vue';
 import { Dialog, Dropdown, FormGroup, TextInput, Checkbox, PasswordInput, NumberInput } from 'pankow';
 import { prettyBinarySize } from 'pankow/utils';
 // TODO REGIONS_UPCLOUD is not used??
@@ -36,7 +36,7 @@ const format = ref('rsync');
 const encryptionPassword = ref('');
 const encryptedFilenames = ref(false);
 const memoryLimit = ref(minMemoryLimit.value);
-const uploadPartSize = ref(1024*1024);
+const uploadPartSize = ref(10*1024*1024);
 const syncConcurrency = ref(10);
 const downloadConcurrency = ref(10);
 const copyConcurrency = ref(10);
@@ -218,6 +218,18 @@ const isValid = computed(() => {
   return true;
 });
 
+watch(provider, (newProvider) => {
+  console.log('provider change', newProvider)
+  if (newProvider === 'scaleway-objectstorage') {
+    // scaleway only supports 1000 parts per object (https://www.scaleway.com/en/docs/s3-multipart-upload/)
+    if (parseInt(uploadPartSize.value) < 100 * 1024 * 1024) uploadPartSize.value = 100 * 1024 * 1024;
+  } else if (newProvider === 's3') {
+    if (parseInt(downloadConcurrency.value) < 30) downloadConcurrency.value = 30;
+    if (parseInt(syncConcurrency.value) < 20) syncConcurrency.value = 20;
+    if (parseInt(copyConcurrency.value) < 500) downloadConcurrency.value = 500;
+  }
+});
+
 onMounted(async () => {
   await getBlockDevices();
   await getMemory();
@@ -237,7 +249,7 @@ defineExpose({
     backupFolder.value = result.backupFolder;
     useHardlinks.value = !result.noHardlinks;
     memoryLimit.value = result.limits.memoryLimit || minMemoryLimit.value;
-    uploadPartSize.value = result.limits.uploadPartSize || (1024*1024);
+    uploadPartSize.value = result.limits.uploadPartSize || (10*1024*1024);
     syncConcurrency.value = result.limits.syncConcurrency || 10;
     downloadConcurrency.value = result.limits.downloadConcurrency || 10;
     copyConcurrency.value = result.limits.copyConcurrency || 10;
@@ -475,9 +487,9 @@ defineExpose({
             <FormGroup v-if="s3like(provider)">
               <label for="uploadPartSizeInput">{{ $t('backups.configureBackupStorage.uploadPartSize') }}: <b>{{ prettyBinarySize(uploadPartSize, 'Default (50 MiB)') }}</b></label>
               <p class="small">{{ $t('backups.configureBackupStorage.uploadPartSizeDescription') }}</p>
-              <input type="range" id="uploadPartSizeInput" v-model="uploadPartSize" list="uploadPartSizeTicks" :step="1024*1024" :min="1024*1024" :max="1024*1024*1024" />
+              <input type="range" id="uploadPartSizeInput" v-model="uploadPartSize" list="uploadPartSizeTicks" :step="1024*1024" :min="10*1024*1024" :max="1024*1024*1024" />
               <datalist id="uploadPartSizeTicks">
-                <option :value="1024*1024"></option>
+                <option :value="1024*1024*10"></option>
                 <option :value="1024*1024*64"></option>
                 <option :value="1024*1024*128"></option>
                 <option :value="1024*1024*256"></option>