mds: enable dirfrags by default in new filesystems

Signed-off-by: john Spray <john.spray@redhat.com>

diff --git a/PendingReleaseNotes b/PendingReleaseNotes
index 47f5b55e3c650a83c252a42feefdddd8c5668dc5..5ecdae2050db8cc2294e3a5af32832a2616715e6 100644 (file)
--- a/PendingReleaseNotes
+++ b/PendingReleaseNotes
@@ -20,7 +20,9 @@
   string will no longer be able to set quotas or any layout fields.  This
   flag previously only restricted modification of the pool and namespace
   fields in layouts.
-
+* CephFS directory fragmentation (large directory support) is enabled
+  by default on new filesystems.  To enable it on existing filesystems
+  use "ceph fs set <fs_name> allow_dirfrags".
 
 12.0.0
 ------

diff --git a/doc/cephfs/dirfrags.rst b/doc/cephfs/dirfrags.rst
index e6bd045b2251d4e745711720ad3e6908066e9c7f..717553fea9afc2e3128b68e7cf0fb26eeacc46a4 100644 (file)
--- a/doc/cephfs/dirfrags.rst
+++ b/doc/cephfs/dirfrags.rst
@@ -14,7 +14,7 @@ here should be left at their default values.
 
 While directory fragmentation enables CephFS to handle very large
 numbers of entries in a single directory, application programmers should
-remain cautious about creating very large directories, as they still
+remain conservative about creating very large directories, as they still
 have a resource cost in situations such as a CephFS client listing
 the directory, where all the fragments must be loaded at once.
 
@@ -27,7 +27,8 @@ Splitting and merging
 
 An MDS will only consider doing splits and merges if the ``mds_bal_frag``
 setting is true in the MDS's configuration file, and the allow_dirfrags
-setting is true in the filesystem map (set on the mons).
+setting is true in the filesystem map (set on the mons).  These settings
+are both true by default since the *Luminous* (12.2.x) release of Ceph.
 
 When an MDS identifies a directory fragment to be split, it does not
 do the split immediately.  Because splitting interrupts metadata IO,

diff --git a/doc/cephfs/experimental-features.rst b/doc/cephfs/experimental-features.rst
index 1f6e3c2af41cb9952d75fb2735a640c21ad38b5c..bdfa998a99e2cfbe99e24f404e30964fe8e7e6e7 100644 (file)
--- a/doc/cephfs/experimental-features.rst
+++ b/doc/cephfs/experimental-features.rst
@@ -12,18 +12,6 @@ what is required to enable them. Note that doing so will *irrevocably* flag maps
 in the monitor as having once enabled this flag to improve debugging and
 support processes.
 
-
-Directory Fragmentation
------------------------
-CephFS directories are generally stored within a single RADOS object. But this has
-certain negative results once they become large enough. The filesystem is capable
-of "fragmenting" these directories into multiple objects. There are no known bugs
-with doing so but it is not sufficiently tested to support at this time.
-
-Directory fragmentation has always been off by default and required setting
-```mds bal frag = true`` in the MDS' config file. It has been further protected
-by requiring the user to set the "allow_dirfrags" flag for Jewel.
-
 Inline data
 -----------
 By default, all CephFS file data is stored in RADOS objects. The inline data
@@ -97,3 +85,20 @@ and may not work together; see above.
 
 Multiple filesystems were available starting in the Jewel release candidates
 but were protected behind the "enable_multiple" flag before the final release.
+
+
+Previously experimental features
+================================
+
+Directory Fragmentation
+-----------------------
+
+Directory fragmentation was considered experimental prior to the *Luminous*
+(12.2.x).  It is now enabled by default on new filesystems.  To enable directory
+fragmentation on filesystems created with older versions of Ceph, set
+the ``allow_dirfrags`` flag on the filesystem:
+
+::
+
+    ceph fs set <filesystem name> allow_dirfrags
+

diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index 8c22e3837824dc8af32acee3028a5d39d5d4a077..222d147a89c92757e1af509f78075756cc1052bf 100644 (file)
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -526,7 +526,7 @@ OPTION(mds_log_max_expiring, OPT_INT, 20)
 OPTION(mds_bal_sample_interval, OPT_DOUBLE, 3.0)  // every 3 seconds
 OPTION(mds_bal_replicate_threshold, OPT_FLOAT, 8000)
 OPTION(mds_bal_unreplicate_threshold, OPT_FLOAT, 0)
-OPTION(mds_bal_frag, OPT_BOOL, false)
+OPTION(mds_bal_frag, OPT_BOOL, true)
 OPTION(mds_bal_split_size, OPT_INT, 10000)
 OPTION(mds_bal_split_rd, OPT_FLOAT, 25000)
 OPTION(mds_bal_split_wr, OPT_FLOAT, 10000)

diff --git a/src/include/ceph_fs.h b/src/include/ceph_fs.h
index 2d1486d94c737ee339e976fb448c86e48e68abc1..479999d06c00edda459dac82a5a8c83f4b0471d9 100644 (file)
--- a/src/include/ceph_fs.h
+++ b/src/include/ceph_fs.h
@@ -239,6 +239,8 @@ struct ceph_mon_subscribe_ack {
 #define CEPH_MDSMAP_ALLOW_CLASSICS (CEPH_MDSMAP_ALLOW_SNAPS | CEPH_MDSMAP_ALLOW_MULTIMDS | \
                                    CEPH_MDSMAP_ALLOW_DIRFRAGS)
 
+#define CEPH_MDSMAP_DEFAULTS CEPH_MDSMAP_ALLOW_DIRFRAGS
+
 /*
  * mds states
  *   > 0 -> in

diff --git a/src/mds/MDSMap.h b/src/mds/MDSMap.h
index e1874459bfb0f7a072b19ebc18e6a57760ff0060..1d8e29b2a36be76474a1e21f4ee9660cfcd540fc 100644 (file)
--- a/src/mds/MDSMap.h
+++ b/src/mds/MDSMap.h
@@ -220,7 +220,7 @@ public:
 public:
   MDSMap() 
     : epoch(0), enabled(false), fs_name(MDS_FS_NAME_DEFAULT),
-      flags(0), last_failure(0),
+      flags(CEPH_MDSMAP_DEFAULTS), last_failure(0),
       last_failure_osd_epoch(0),
       tableserver(0), root(0),
       session_timeout(0),