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, 24 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index 6ab899a16cf..9701c6b939c 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -2684,10 +2684,14 @@ volume_volgen_graph_build_clusters (volgen_graph_t *graph,
                                                        "%s-replicate-%d"};
         char                    *stripe_args[]      = {"cluster/stripe",
                                                        "%s-stripe-%d"};
+        char                    *disperse_args[]    = {"cluster/disperse",
+                                                       "%s-disperse-%d"};
+        char                    option[32]          = "";
         int                     rclusters           = 0;
         int                     clusters            = 0;
         int                     dist_count          = 0;
         int                     ret                 = -1;
+        xlator_t *              ec                  = NULL;
 
         if (!volinfo->dist_leaf_count)
                 goto out;
@@ -2737,6 +2741,26 @@ volume_volgen_graph_build_clusters (volgen_graph_t *graph,
                 if (clusters < 0)
                         goto out;
                 break;
+        case GF_CLUSTER_TYPE_DISPERSE:
+                clusters = volgen_graph_build_clusters (graph, volinfo,
+                                                        disperse_args[0],
+                                                        disperse_args[1],
+                                                        volinfo->brick_count,
+                                                        volinfo->disperse_count);
+                if (clusters < 0)
+                        goto out;
+
+                sprintf(option, "%d", volinfo->redundancy_count);
+                ec = first_of (graph);
+                while (clusters-- > 0) {
+                        ret = xlator_set_option (ec, "redundancy", option);
+                        if (ret)
+                                goto out;
+
+                        ec = ec->next;
+                }
+
+                break;
         default:
                 gf_log ("", GF_LOG_ERROR, "volume inconsistency: "
                         "unrecognized clustering type");