os/bluestore: add bluestore fragmentation micros to prometheus

High fragmentation is one of the factors affecting performance decrease,
add it to prometheus, it helps to us monitor fragmentation changes.

Signed-off-by: Yite Gu <yitegu0@gmail.com>
(cherry picked from commit 8fed26a185215d1a92c88544fd64f84a94bb106e)

diff --git a/src/os/bluestore/BlueStore.cc b/src/os/bluestore/BlueStore.cc
index aa14d0204f7aaad4f52b0f855a33def65b2b56eb..3086a303cb30489cd46d3fb6e02f0d46bb08616a 100644 (file)
--- a/src/os/bluestore/BlueStore.cc
+++ b/src/os/bluestore/BlueStore.cc
@@ -5028,7 +5028,9 @@ void BlueStore::_init_logger()
            PerfCountersBuilder::PRIO_CRITICAL,
            unit_t(UNIT_BYTES));
   b.add_u64(l_bluestore_fragmentation, "fragmentation_micros",
-            "How fragmented bluestore free space is (free extents / max possible number of free extents) * 1000");
+            "How fragmented bluestore free space is (free extents / max possible number of free extents) * 1000",
+           "fbss",
+           PerfCountersBuilder::PRIO_USEFUL);
   b.add_u64(l_bluestore_alloc_unit, "alloc_unit",
            "allocation unit size in bytes",
            "au_b",