config: lower default omap entries recovered at once

For large omap DBs, reading 64k leads to heartbeat timeouts.  There
are numerous callchains leading to this recovery step, many of which
do not have heartbeat handles, so for an easily backported version
just change the default number of entries read. DBs approaching 100GB
may require an even lower setting, but this should be good enough for
most clusters, without sacrificing recovery speed.

Fixes: http://tracker.ceph.com/issues/21897
Signed-off-by: Josh Durgin <jdurgin@redhat.com>

diff --git a/src/common/options.cc b/src/common/options.cc
index e7d767bb9eaaeb06276a5dfcf8cc493e29dc6ffc..fbd61838dee28ce457eb7d71267690be13e43520 100644 (file)
--- a/src/common/options.cc
+++ b/src/common/options.cc
@@ -2594,7 +2594,7 @@ std::vector<Option> get_global_options() {
     .set_description(""),
 
     Option("osd_recovery_max_omap_entries_per_chunk", Option::TYPE_UINT, Option::LEVEL_ADVANCED)
-    .set_default(64000)
+    .set_default(8096)
     .set_description(""),
 
     Option("osd_copyfrom_max_chunk", Option::TYPE_UINT, Option::LEVEL_ADVANCED)