os/newstore: set rocksdb default options

 max_write_buffer_number=16
 min_write_buffer_number_to_merge=6

This cuts the amount of short-lived WAL data that gets
rewritten by roughly a factor of 6.

Signed-off-by: Sage Weil <sage@redhat.com>

diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index dbad270a3b9bfeed8f3f4c190e0ddf50f9afee6b..1d6edd8d03c8878fed5e2b65d53137b6a9418b9b 100644 (file)
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -812,7 +812,7 @@ OPTION(memstore_page_size, OPT_U64, 64 << 10)
 OPTION(newstore_max_dir_size, OPT_U32, 1000000)
 OPTION(newstore_onode_map_size, OPT_U32, 1024)   // onodes per collection
 OPTION(newstore_backend, OPT_STR, "rocksdb")
-OPTION(newstore_backend_options, OPT_STR, "")
+OPTION(newstore_backend_options, OPT_STR, "max_write_buffer_number=16,min_write_buffer_number_to_merge=6")
 OPTION(newstore_fail_eio, OPT_BOOL, true)
 OPTION(newstore_sync_io, OPT_BOOL, false)  // perform initial io synchronously
 OPTION(newstore_sync_transaction, OPT_BOOL, false)  // perform kv txn synchronously