How to have an Ionic >=2 scrollable ion-list under fixed search bar

ion-content does not have scroll input property to disable it.
If you need to have searchbar always visible, I suggest you place it in a toolbar.

<ion-header>
      <ion-navbar>
        <ion-title>{{ appName }}</ion-title>
       </ion-navbar>
       <ion-toolbar>
           <ion-searchbar></ion-searchbar>
       </ion-toolbar>
</ion-header>

Or use ion-scroll with a fixed height.

<ion-grid>
    <!-- Row 2 Scrollable list -->
    <ion-row>
      <ion-col>
          <ion-searchbar></ion-searchbar>
      </ion-col>
    </ion-row>
    <ion-row>
      <ion-col>
        <ion-scroll style="width:100%;height:100vh" scrollY="true">
           <ion-list scroll="true">
          <ion-item *ngFor="let item of data">
            <div>{{item}}</div>
          </ion-item>
        </ion-list>
        </ion-scroll>

      </ion-col>
    </ion-row>

  </ion-grid>

Sample Plunkr

Update: To answer @JohnDoe's comment.. in order to get scroll list to take the height of rest of the screen use Viewport percentage height to set the height of ion-scroll.