Merge pull request #1106 from noobaa/evgb-ContentTieringDemo

Evgb content tiering demo
noobaa · Apr 27, 2016 · ad4ff7e · ad4ff7e
2 parents 88a9c0a + f03ae23
commit ad4ff7e
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Showing 3 changed files with 24 additions and 4 deletions.
diff --git a/src/server/mapper/block_allocator.js b/src/server/mapper/block_allocator.js
@@ -93,9 +93,12 @@ function refresh_pool_alloc(pool) {
  * allocate_node
  *
  * @param avoid_nodes array of node ids to avoid
+ * @param content_tiering_params - in case of content tiering, the additional
+ * replicas will be saved in nodes that have the best disk read latency, but only
+ * from the chunk of nodes that we've received in pools.
  *
  */
-function allocate_node(pools, avoid_nodes) {
+function allocate_node(pools, avoid_nodes, content_tiering_params) {
     let pool_set = _.map(pools, pool => pool._id.toString()).sort().join(',');
     let alloc_group =
         alloc_group_by_pool_set[pool_set] =
@@ -105,6 +108,18 @@ function allocate_node(pools, avoid_nodes) {
                 return group && group.nodes;
             })))
         };
+
+    // If we are allocating a node for content tiering special replicas,
+    // we should run an additional sort, in order to get the best read latency nodes
+    if (content_tiering_params && content_tiering_params.special_replica) {
+        alloc_group.nodes = _.sortBy(alloc_group.nodes, node =>
+            // In order to sort the nodes by the best read latency values.
+            // We need to get the average of all the latency disk read values,
+            // and sort the nodes by the average that we've calculated.
+            _.sum(node.latency_of_disk_read) / node.latency_of_disk_read.length
+        );
+    }
+
     let num_nodes = alloc_group ? alloc_group.nodes.length : 0;
     dbg.log1('allocate_node: pool_set', pool_set,
         'num_nodes', num_nodes,
@@ -133,4 +148,4 @@ function get_round_robin(nodes) {
     var rr = (nodes.rr || 0) % nodes.length;
     nodes.rr = rr + 1;
     return nodes[rr];
-}
+}
diff --git a/src/server/mapper/map_builder.js b/src/server/mapper/map_builder.js
@@ -110,7 +110,11 @@ class MapBuilder {
                     'digest_type',
                     'digest_b64');
                 block._id = md_store.make_md_id();
-                let node = block_allocator.allocate_node(alloc.pools, avoid_nodes);
+                // We send an additional flag in order to allocate
+                // replicas of content tiering feature on the best read latency nodes
+                let node = block_allocator.allocate_node(alloc.pools, avoid_nodes, {
+                    special_replica: true
+                });
                 if (!node) {
                     dbg.error('MapBuilder: no nodes for allocation');
                     chunk.had_errors = true;

diff --git a/src/server/stores/nodes_store.js b/src/server/stores/nodes_store.js
@@ -22,6 +22,7 @@ const NODE_FIELDS_FOR_MAP = Object.freeze({
     heartbeat: 1,
     rpc_address: 1,
     storage: 1,
+    latency_of_disk_read: 1,
 });
 
 module.exports = {
@@ -175,7 +176,7 @@ function aggregate_nodes_by_pool(query) {
             }
         ))
         .then(res => {
-            var bins = {};              
+            var bins = {};
             _.each(res, r => {
                 var t = bins[r._id[0]] = bins[r._id[0]] || {};
                 t[r._id[1]] = r.value;