diff --git a/plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptor.java b/plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptor.java
index 607dd620f61..b85be041e48 100644
--- a/plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptor.java
+++ b/plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptor.java
@@ -552,12 +552,12 @@ public class ScaleIOStorageAdaptor implements StorageAdaptor {
 
     /**
      * Calculates usable size from raw size, assuming qcow2 requires 192k/1GB for metadata
-     * We also remove 32MiB for potential encryption/safety factor.
+     * We also remove 128MiB for encryption/fragmentation/safety factor.
      * @param raw size in bytes
      * @return usable size in bytesbytes
      */
     public static long getUsableBytesFromRawBytes(Long raw) {
-        long usable = raw - (32 << 20) - ((raw >> 30) * 200704);
+        long usable = raw - (128 << 20) - ((raw >> 30) * 200704);
         if (usable < 0) {
             usable = 0L;
         }
diff --git a/plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptorTest.java b/plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptorTest.java
index cea8886d64e..25fab1a6ff8 100644
--- a/plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptorTest.java
+++ b/plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/storage/ScaleIOStorageAdaptorTest.java
@@ -26,9 +26,9 @@ import org.mockito.junit.MockitoJUnitRunner;
 public class ScaleIOStorageAdaptorTest {
     @Test
     public void getUsableBytesFromRawBytesTest() {
-        Assert.assertEquals("Overhead calculated for 8Gi size", 8554774528L, ScaleIOStorageAdaptor.getUsableBytesFromRawBytes(8L << 30));
-        Assert.assertEquals("Overhead calculated for 4Ti size", 4294130925568L, ScaleIOStorageAdaptor.getUsableBytesFromRawBytes(4000L << 30));
-        Assert.assertEquals("Overhead calculated for 500Gi size", 536737005568L, ScaleIOStorageAdaptor.getUsableBytesFromRawBytes(500L << 30));
+        Assert.assertEquals("Overhead calculated for 8Gi size", 8454111232L, ScaleIOStorageAdaptor.getUsableBytesFromRawBytes(8L << 30));
+        Assert.assertEquals("Overhead calculated for 4Ti size", 4294030262272L, ScaleIOStorageAdaptor.getUsableBytesFromRawBytes(4000L << 30));
+        Assert.assertEquals("Overhead calculated for 500Gi size", 536636342272L, ScaleIOStorageAdaptor.getUsableBytesFromRawBytes(500L << 30));
         Assert.assertEquals("Unsupported small size", 0, ScaleIOStorageAdaptor.getUsableBytesFromRawBytes(1L));
     }
 }