Improve bulk CI docs (#104)

diff --git a/docs/bulk-test.md b/docs/bulk-test.md
index 17076e7..071cce8 100644
--- a/docs/bulk-test.md
+++ b/docs/bulk-test.md
@@ -30,6 +30,9 @@
   ./bin/cingest bulk /tmp/bt/$i
 done
 
+# Optionally, copy data before importing.  This can be useful in debugging problems.
+hadoop distcp hdfs://$NAMENODE/tmp/bt hdfs://$NAMENODE/tmp/bt-copy
+
 for i in $(seq 1 10); do
   (
     echo table ci
@@ -53,6 +56,12 @@
 scan -t accumulo.metadata -c loaded
 ```
 
+Additionally check that no rfiles exists in the source dir.
+
+```bash
+hadoop fs -ls -R /tmp/bt | grep rf
+```
+
 The referenced counts output by `cingest verify` should equal :
 
 ```