glusterd: CLI commands to create and manage tiered volumes.

A tiered volume is a normal volume with some number of new bricks
representing "hot" storage. The "hot" bricks can be attached or
detached dynamically to a normal volume. When this happens, a new graph
is constructed. The root of the new graph is an instance of the tier
translator. One subvolume of the tier translator leads to the old volume,
and another leads to the new hot bricks.

attach-tier <VOLNAME> [<replica> <COUNT>] <NEW-BRICK> ... [force]

volume detach-tier <VOLNAME> [replica <COUNT>] <BRICK>
... <start|stop|status|commit|force>

gluster volume rebalance <volume> tier start

gluster volume rebalance <volume> tier stop

gluster volume rebalance <volume> tier status

The "tier start" CLI command starts a server side daemon. The daemon
initiates file level migration based on caching policies. The daemon's
status can be monitored and stopped.

Note development on the "tier status" command is incomplete. It will be
added in a subsequent patch.

When the "hot" storage is detached, the tier translator is removed
from the graph and the tiered volume reverts to its original state as
described in the volume's info file.

For more background and design see the feature page [1].

[1]
http://www.gluster.org/community/documentation/index.php/Features/data-classification

Change-Id: Ic8042ce37327b850b9e199236e5be3dae95d2472
BUG: 1194753
Signed-off-by: Dan Lambright <dlambrig@redhat.com>
Reviewed-on: http://review.gluster.org/9753
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-rebalance.c b/xlators/mgmt/glusterd/src/glusterd-rebalance.c
index ba67df436ff..0d66571300f 100644
--- a/xlators/mgmt/glusterd/src/glusterd-rebalance.c
+++ b/xlators/mgmt/glusterd/src/glusterd-rebalance.c
@@ -278,6 +278,13 @@ glusterd_handle_defrag_start (glusterd_volinfo_t *volinfo, char *op_errstr,
                          "--xlator-option", "*replicate*.readdir-failover=off",
                          "--xlator-option", "*dht.readdir-optimize=on",
                          NULL);
+
+        if (volinfo->type == GF_CLUSTER_TYPE_TIER) {
+                runner_add_arg (&runner, "--xlator-option");
+                runner_argprintf (&runner,
+                                  "*tier-dht.xattr-name=trusted.tier-gfid");
+        }
+
         runner_add_arg (&runner, "--xlator-option");
         runner_argprintf ( &runner, "*dht.rebalance-cmd=%d",cmd);
         runner_add_arg (&runner, "--xlator-option");
@@ -487,6 +494,7 @@ __glusterd_handle_defrag_volume (rpcsvc_request_t *req)
                 goto out;
 
         if ((cmd == GF_DEFRAG_CMD_STATUS) ||
+            (cmd == GF_DEFRAG_CMD_STATUS_TIER) ||
               (cmd == GF_DEFRAG_CMD_STOP)) {
                 ret = glusterd_op_begin (req, GD_OP_DEFRAG_BRICK_VOLUME,
                                          dict, msg, sizeof (msg));
@@ -556,6 +564,7 @@ glusterd_op_stage_rebalance (dict_t *dict, char **op_errstr)
         switch (cmd) {
         case GF_DEFRAG_CMD_START:
         case GF_DEFRAG_CMD_START_LAYOUT_FIX:
+        case GF_DEFRAG_CMD_START_TIER:
                 /* Check if the connected clients are all of version
                  * glusterfs-3.6 and higher. This is needed to prevent some data
                  * loss issues that could occur when older clients are connected
@@ -690,7 +699,9 @@ glusterd_op_rebalance (dict_t *dict, char **op_errstr, dict_t *rsp_dict)
         /* Set task-id, if available, in op_ctx dict for operations other than
          * start
          */
-        if (cmd == GF_DEFRAG_CMD_STATUS || cmd == GF_DEFRAG_CMD_STOP) {
+        if (cmd == GF_DEFRAG_CMD_STATUS ||
+            cmd == GF_DEFRAG_CMD_STOP ||
+            cmd == GF_DEFRAG_CMD_STATUS_TIER) {
                 if (!uuid_is_null (volinfo->rebal.rebalance_id)) {
                         ctx = glusterd_op_get_ctx ();
                         if (!ctx) {
@@ -720,6 +731,7 @@ glusterd_op_rebalance (dict_t *dict, char **op_errstr, dict_t *rsp_dict)
         case GF_DEFRAG_CMD_START:
         case GF_DEFRAG_CMD_START_LAYOUT_FIX:
         case GF_DEFRAG_CMD_START_FORCE:
+        case GF_DEFRAG_CMD_START_TIER:
                 /* Reset defrag status to 'NOT STARTED' whenever a
                  * remove-brick/rebalance command is issued to remove
                  * stale information from previous run.
@@ -791,6 +803,7 @@ glusterd_op_rebalance (dict_t *dict, char **op_errstr, dict_t *rsp_dict)
                 break;
 
         case GF_DEFRAG_CMD_STATUS:
+        case GF_DEFRAG_CMD_STATUS_TIER:
                 break;
         default:
                 break;