osd: Add config option to disable new scrubs during recovery

A new config option allows for configuring if the OSD will schedule
a new scrub while recovery is active.

When set to false no new scrubs will be initiated by the OSD while
there are recovery threads active on that OSD.

Signed-off-by: Wido den Hollander <wido@42on.com>

src/common/config_opts.h

@@ -771,6 +771,7 @@ OPTION(osd_max_push_cost, OPT_U64, 8<<20)  // max size of push message
 OPTION(osd_max_push_objects, OPT_U64, 10)  // max objects in single push op
 OPTION(osd_recovery_forget_lost_objects, OPT_BOOL, false)   // off for now
 OPTION(osd_max_scrubs, OPT_INT, 1)
+OPTION(osd_scrub_during_recovery, OPT_BOOL, true) // Allow new scrubs to start while recovery is active on the OSD
 OPTION(osd_scrub_begin_hour, OPT_INT, 0)
 OPTION(osd_scrub_end_hour, OPT_INT, 24)
 OPTION(osd_scrub_load_threshold, OPT_FLOAT, 0.5)

src/osd/OSD.cc

@@ -1053,7 +1053,9 @@ bool OSDService::can_inc_scrubs_pending()
   bool can_inc = false;
   Mutex::Locker l(sched_scrub_lock);
 
-  if (scrubs_pending + scrubs_active < cct->_conf->osd_max_scrubs) {
+  if (!cct->_conf->osd_scrub_during_recovery && recovery_ops_active > 0) {
+    dout(20) << __func__ << "not scheduling scrub because recovery is active" << dendl;
+  } else if (scrubs_pending + scrubs_active < cct->_conf->osd_max_scrubs) {
     dout(20) << __func__ << " " << scrubs_pending << " -> " << (scrubs_pending+1)
 	     << " (max " << cct->_conf->osd_max_scrubs << ", active " << scrubs_active << ")" << dendl;
     can_inc = true;