cli/glusterd: Added support for dispersed volumes

Two new options have been added to the 'create' command of the cli
interface:

    disperse [<count>] redundancy <count>

Both are optional. A dispersed volume is created by specifying, at
least, one of them. If 'disperse' is missing or it's present but
'<count>' does not, the number of bricks enumerated in the command
line is taken as the disperse count.

If 'redundancy' is missing, the lowest optimal value is assumed. A
configuration is considered optimal (for most workloads) when the
disperse count - redundancy count is a power of 2. If the resulting
redundancy is 1, the volume is created normally, but if it's greater
than 1, a warning is shown to the user and he/she must answer yes/no
to continue volume creation. If there isn't any optimal value for
the given number of bricks, a warning is also shown and, if the user
accepts, a redundancy of 1 is used.

If 'redundancy' is specified and the resulting volume is not optimal,
another warning is shown to the user.

A distributed-disperse volume can be created using a number of bricks
multiple of the disperse count.

Change-Id: Iab93efbe78e905cdb91f54f3741599f7ea6645e4
BUG: 1118629
Signed-off-by: Xavier Hernandez <xhernandez@datalab.es>
Reviewed-on: http://review.gluster.org/7782
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-volume-ops.c b/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
index 53beebe055..f23a9eb96b 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volume-ops.c
@@ -1689,6 +1689,27 @@ glusterd_op_create_volume (dict_t *dict, char **op_errstr)
                                 "replica count for volume %s", volname);
                         goto out;
                 }
+        } else if (GF_CLUSTER_TYPE_DISPERSE == volinfo->type) {
+                ret = dict_get_int32 (dict, "disperse-count",
+                                      &volinfo->disperse_count);
+                if (ret) {
+                        gf_log (this->name, GF_LOG_ERROR, "Failed to get "
+                                 "disperse count for volume %s", volname);
+                        goto out;
+                }
+                ret = dict_get_int32 (dict, "redundancy-count",
+                                      &volinfo->redundancy_count);
+                if (ret) {
+                        gf_log (this->name, GF_LOG_ERROR, "Failed to get "
+                                 "redundancy count for volume %s", volname);
+                        goto out;
+                }
+                if (priv->op_version < GD_OP_VERSION_3_6_0) {
+                        gf_log (this->name, GF_LOG_ERROR, "Disperse volume "
+                                "needs op-version 3.6.0 or higher");
+                        ret = -1;
+                        goto out;
+                }
         }
 
         /* dist-leaf-count is the count of brick nodes for a given