diff --git a/include/bitcoin/node/block_arena.hpp b/include/bitcoin/node/block_arena.hpp
index d0ad096a..de928447 100644
--- a/include/bitcoin/node/block_arena.hpp
+++ b/include/bitcoin/node/block_arena.hpp
@@ -26,7 +26,7 @@
 namespace libbitcoin {
 namespace node {
 
-/// Thread UNSAFE linked-linear memory arena.
+/// Thread UNSAFE detachable linked-linear memory arena.
 class BCN_API block_arena final
   : public arena
 {
diff --git a/include/bitcoin/node/full_node.hpp b/include/bitcoin/node/full_node.hpp
index aa5b6eb8..c0b4e6bf 100644
--- a/include/bitcoin/node/full_node.hpp
+++ b/include/bitcoin/node/full_node.hpp
@@ -30,10 +30,17 @@ namespace libbitcoin {
 namespace node {
 
 /// Thread safe.
+/// WARNING: when full node is using block_memory controller, all shared block
+/// components invalidate when the block destructs. Lifetime of the block is
+/// assured for the extent of all methods below, however if a sub-object is
+/// retained by shared_ptr, beyond method completion, a copy of the block
+/// shared_ptr must also be be retained. Taking a block or sub-object copy is
+/// insufficient, as copies are shallow (copy internal shared_ptr objects).
 class BCN_API full_node
   : public network::p2p
 {
 public:
+    using memory_controller = block_memory;
     using store = node::store;
     using query = node::query;
     typedef std::shared_ptr<full_node> ptr;
@@ -166,10 +173,10 @@ class BCN_API full_node
 
     // These are thread safe.
     const configuration& config_;
+    memory_controller memory_;
     query& query_;
 
     // These are protected by strand.
-    block_memory memory_;
     chaser_block chaser_block_;
     chaser_header chaser_header_;
     chaser_check chaser_check_;
diff --git a/include/bitcoin/node/sessions/attach.hpp b/include/bitcoin/node/sessions/attach.hpp
index f618c343..5e8177e2 100644
--- a/include/bitcoin/node/sessions/attach.hpp
+++ b/include/bitcoin/node/sessions/attach.hpp
@@ -106,7 +106,6 @@ class attach
     network::channel::ptr create_channel(const network::socket::ptr& socket,
         bool quiet) NOEXCEPT override
     {
-        // This memory arena is NOT thread safe.
         return std::make_shared<network::channel>(session::get_memory(),
             network::session::log, socket, network::session::settings(),
             network::session::create_key(), quiet);
diff --git a/src/full_node.cpp b/src/full_node.cpp
index 6a9d1f5d..653678bd 100644
--- a/src/full_node.cpp
+++ b/src/full_node.cpp
@@ -40,9 +40,8 @@ full_node::full_node(query& query, const configuration& configuration,
     const logger& log) NOEXCEPT
   : p2p(configuration.network, log),
     config_(configuration),
+    memory_(config_.node.allocation_multiple, config_.network.threads),
     query_(query),
-    memory_(configuration.node.allocation_multiple,
-        configuration.network.threads),
     chaser_block_(*this),
     chaser_header_(*this),
     chaser_check_(*this),