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, 6 insertions, 3 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd.h b/xlators/mgmt/glusterd/src/glusterd.h
index ad280eda053..bac1598598b 100644
--- a/xlators/mgmt/glusterd/src/glusterd.h
+++ b/xlators/mgmt/glusterd/src/glusterd.h
@@ -302,9 +302,6 @@ typedef struct tier_info_ {
         int                       hot_type;
         int                       hot_brick_count;
         int                       hot_replica_count;
-        int                       hot_disperse_count;
-        /*Commented for now Dan's DHT Tier patch will have it*/
-        /*tier_group_t             *root;*/
 } gd_tier_info_t;
 
 struct glusterd_volinfo_ {
@@ -814,6 +811,12 @@ int
 glusterd_handle_add_brick (rpcsvc_request_t *req);
 
 int
+glusterd_handle_attach_tier (rpcsvc_request_t *req);
+
+int
+glusterd_handle_detach_tier (rpcsvc_request_t *req);
+
+int
 glusterd_handle_replace_brick (rpcsvc_request_t *req);
 
 int