osd: introduce simple sleep during scrub

This option is similar to osd_snap_trim_sleep: simply inject an optional
sleep in the thread that is doing scrub work.  This is a very kludgey and
coarse knob for limiting the impact of scrub on the cluster, but can help
until we have a more robust and elegant solution.

Only sleep if we are in the NEW_CHUNK state to avoid delaying processing of
an in-progress chunk.  In this state nothing is blocked on anything.
Conveniently, chunky_scrub() requeues itself for each new chunk.

Backport: firefly, dumpling
Signed-off-by: Sage Weil <sage@inktank.com>

diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index 741d481c117243cf183e8c5012e95b1acf8d3d19..29ff66349ea6aae85a500afd3f5357e23afdf54b 100644 (file)
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -518,6 +518,7 @@ OPTION(osd_scrub_min_interval, OPT_FLOAT, 60*60*24)    // if load is low
 OPTION(osd_scrub_max_interval, OPT_FLOAT, 7*60*60*24)  // regardless of load
 OPTION(osd_scrub_chunk_min, OPT_INT, 5)
 OPTION(osd_scrub_chunk_max, OPT_INT, 25)
+OPTION(osd_scrub_sleep, OPT_FLOAT, 0)   // sleep between [deep]scrub ops
 OPTION(osd_deep_scrub_interval, OPT_FLOAT, 60*60*24*7) // once a week
 OPTION(osd_deep_scrub_stride, OPT_INT, 524288)
 OPTION(osd_scan_list_ping_tp_interval, OPT_U64, 100)

diff --git a/src/osd/PG.cc b/src/osd/PG.cc
index b77706e4a393c2fd5ee5854032dc2984b38071df..613e9c3c5a695aee505270450ad39511fdde308b 100644 (file)
--- a/src/osd/PG.cc
+++ b/src/osd/PG.cc
@@ -3509,6 +3509,17 @@ void PG::replica_scrub(
 void PG::scrub(ThreadPool::TPHandle &handle)
 {
   lock();
+  if (g_conf->osd_scrub_sleep > 0 &&
+      (scrubber.state == PG::Scrubber::NEW_CHUNK ||
+       scrubber.state == PG::Scrubber::INACTIVE)) {
+    dout(20) << __func__ << " state is INACTIVE|NEW_CHUNK, sleeping" << dendl;
+    unlock();
+    utime_t t;
+    t.set_from_double(g_conf->osd_scrub_sleep);
+    t.sleep();
+    lock();
+    dout(20) << __func__ << " slept for " << t << dendl;
+  }
   if (deleting) {
     unlock();
     return;