filejournal: journal write cache is safe on >= 2.6.33

diff --git a/src/os/FileJournal.cc b/src/os/FileJournal.cc
index 6cead38044e37dc780687c932518eb97c5408aeb..f20f0a556c9d87b1db8d1f7a2fb38a2c265a9b7d 100644 (file)
--- a/src/os/FileJournal.cc
+++ b/src/os/FileJournal.cc
@@ -105,11 +105,13 @@ int FileJournal::_open(bool forwrite, bool create)
            int on;
            if (sscanf(s, " write-caching =  %d", &on) == 1) {
              if (on) {
-               dout(0) << "WARNING: disk write cache is ON, journaling will not be reliable" << dendl;
+               dout(0) << "WARNING: disk write cache is ON; journaling will not be reliable" << dendl;
+               dout(0) << "         on kernels prior to 2.6.33 (recent kernels are safe)" << dendl;
                dout(0) << "         disable with 'hdparm -W 0 " << fn << "'" << dendl;
                cout << TEXT_RED
                     << " ** WARNING: disk write cache is ON on " << fn << ".\n"
-                    << "    Journaling will not be reliable.  Disable write cache with\n"
+                    << "    Journaling will not be reliable on kernels prior to 2.6.33\n"
+                    << "    (recent kernels are safe).  You can disable the write cache with\n"
                     << "    'hdparm -W 0 " << fn << "'"
                     << TEXT_NORMAL
                     << std::endl;