diff --git a/swh/loader/svn/loader.py b/swh/loader/svn/loader.py
--- a/swh/loader/svn/loader.py
+++ b/swh/loader/svn/loader.py
@@ -7,14 +7,14 @@
 swh-storage.
 
 """
-
 import os
+import pty
 import re
 import shutil
 import tempfile
 
 from mmap import mmap, ACCESS_WRITE
-from subprocess import run, PIPE
+from subprocess import Popen
 
 from swh.model import hashutil
 from swh.model.from_disk import Directory
@@ -25,7 +25,8 @@
 
 from . import svn, converters
 from .utils import (
-    init_svn_repo_from_dump, init_svn_repo_from_archive_dump
+    init_svn_repo_from_dump, init_svn_repo_from_archive_dump,
+    OutputStream
 )
 from .exception import SvnLoaderUneventful
 from .exception import SvnLoaderHistoryAltered
@@ -650,9 +651,21 @@
         dump_temp_dir = tempfile.mkdtemp(dir=self.temp_dir)
         dump_name = ''.join(c for c in svn_url if c.isalnum())
         dump_path = '%s/%s.svndump' % (dump_temp_dir, dump_name)
+        stderr_lines = []
         self.log.debug('Executing %s' % ' '.join(svnrdump_cmd))
         with open(dump_path, 'wb') as dump_file:
-            svnrdump = run(svnrdump_cmd, stdout=dump_file, stderr=PIPE)
+            stderr_r, stderr_w = pty.openpty()
+            svnrdump = Popen(svnrdump_cmd, stdout=dump_file, stderr=stderr_w)
+            os.close(stderr_w)
+            stderr_stream = OutputStream(stderr_r)
+            readable = True
+            while readable:
+                lines, readable = stderr_stream.read_lines()
+                stderr_lines += lines
+                for line in lines:
+                    self.log.debug(line)
+            svnrdump.wait()
+            os.close(stderr_r)
 
         if svnrdump.returncode == 0:
             return dump_path
@@ -661,14 +674,13 @@
         # can be loaded.
 
         # Get the stderr line with latest dumped revision
-        stderr_lines = svnrdump.stderr.split(b'\n')
         last_dumped_rev = None
         if len(stderr_lines) > 1:
             last_dumped_rev = stderr_lines[-2]
 
         if last_dumped_rev:
             # Get the latest dumped revision number
-            matched_rev = re.search(b'.*revision ([0-9]+)', last_dumped_rev)
+            matched_rev = re.search('.*revision ([0-9]+)', last_dumped_rev)
             last_dumped_rev = int(matched_rev.group(1)) if matched_rev else -1
             # Check if revisions inside the dump file can be loaded anyway
             if last_dumped_rev > last_loaded_svn_rev:
diff --git a/swh/loader/svn/tests/test_utils.py b/swh/loader/svn/tests/test_utils.py
--- a/swh/loader/svn/tests/test_utils.py
+++ b/swh/loader/svn/tests/test_utils.py
@@ -3,8 +3,12 @@
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
+import os
+import pty
 import unittest
 
+from subprocess import Popen
+
 from swh.loader.svn import utils
 
 
@@ -25,3 +29,18 @@
                          utils.strdate_to_timestamp(''))
         self.assertEqual({'seconds': 0, 'microseconds': 0},
                          utils.strdate_to_timestamp(None))
+
+    def test_outputstream(self):
+        stdout_r, stdout_w = pty.openpty()
+        echo = Popen(['echo', '-e', 'foo\nbar\nbaz'], stdout=stdout_w)
+        os.close(stdout_w)
+        stdout_stream = utils.OutputStream(stdout_r)
+        lines = []
+        while True:
+            current_lines, readable = stdout_stream.read_lines()
+            lines += current_lines
+            if not readable:
+                break
+        echo.wait()
+        os.close(stdout_r)
+        self.assertEqual(lines, ['foo', 'bar', 'baz'])
diff --git a/swh/loader/svn/utils.py b/swh/loader/svn/utils.py
--- a/swh/loader/svn/utils.py
+++ b/swh/loader/svn/utils.py
@@ -3,6 +3,7 @@
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
+import errno
 import os
 import tempfile
 import shutil
@@ -33,6 +34,48 @@
     return ts
 
 
+class OutputStream:
+    """Helper class to read lines from a program output while
+    it is running
+
+    Args:
+        fileno (int): File descriptor of a program output stream
+            opened in text mode
+    """
+
+    def __init__(self, fileno):
+        self._fileno = fileno
+        self._buffer = ''
+
+    def read_lines(self):
+        """
+        Read available lines from the output stream and return them.
+
+        Returns:
+            Tuple[List[str], bool]: A tuple whose first member is the read
+                lines and second member a boolean indicating if there are
+                still some other lines available to read.
+        """
+        try:
+            output = os.read(self._fileno, 1000).decode()
+        except OSError as e:
+            if e.errno != errno.EIO:
+                raise
+            output = ''
+        output = output.replace('\r\n', '\n')
+        lines = output.split('\n')
+        lines[0] = self._buffer + lines[0]
+
+        if output:
+            self._buffer = lines[-1]
+            return (lines[:-1], True)
+        else:
+            self._buffer = ''
+            if len(lines) == 1 and not lines[0]:
+                lines = []
+            return (lines, False)
+
+
 def init_svn_repo_from_dump(dump_path, prefix=None, suffix=None,
                             root_dir='/tmp', gzip=False):
     """Given a path to a svn dump.