HDFS-12094. Log torrent when none isa-l EC is used. Contributed by LiXin Ge.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/CodecUtil.java

@@ -178,8 +178,10 @@ public final class CodecUtil {
         }
       } catch (LinkageError | Exception e) {
         // Fallback to next coder if possible
-        LOG.warn("Failed to create raw erasure encoder " + rawCoderName +
-            ", fallback to next codec if possible", e);
+        if (LOG.isDebugEnabled()) {
+          LOG.debug("Failed to create raw erasure encoder " + rawCoderName +
+              ", fallback to next codec if possible", e);
+        }
       }
     }
     throw new IllegalArgumentException("Fail to create raw erasure " +
@@ -198,12 +200,14 @@ public final class CodecUtil {
         }
       } catch (LinkageError | Exception e) {
         // Fallback to next coder if possible
-        LOG.warn("Failed to create raw erasure decoder " + rawCoderName +
-            ", fallback to next codec if possible", e);
+        if (LOG.isDebugEnabled()) {
+          LOG.debug("Failed to create raw erasure decoder " + rawCoderName +
+                  ", fallback to next codec if possible", e);
+        }
       }
     }
     throw new IllegalArgumentException("Fail to create raw erasure " +
-        "encoder with given codec: " + codecName);
+        "decoder with given codec: " + codecName);
   }
 
   private static ErasureCodec createCodec(Configuration conf,

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/ErasureCodeNative.java

@@ -50,6 +50,11 @@ public final class ErasureCodeNative {
       }
       LOADING_FAILURE_REASON = problem;
     }
+
+    if (LOADING_FAILURE_REASON != null) {
+      LOG.warn("ISA-L support is not available in your platform... " +
+              "using builtin-java codec where applicable");
+    }
   }
 
   private ErasureCodeNative() {}