diff --git a/apis/io-engine/protobuf/v1/replica.proto b/apis/io-engine/protobuf/v1/replica.proto
index 65598d3..60b109a 100644
--- a/apis/io-engine/protobuf/v1/replica.proto
+++ b/apis/io-engine/protobuf/v1/replica.proto
@@ -15,6 +15,7 @@ service ReplicaRpc {
   rpc ListReplicas (ListReplicaOptions) returns (ListReplicasResponse) {}
   rpc ShareReplica (ShareReplicaRequest) returns (Replica) {}
   rpc UnshareReplica (UnshareReplicaRequest) returns (Replica) {}
+  rpc ResizeReplica (ResizeReplicaRequest) returns (Replica) {}
 }
 
 // Replica space usage
@@ -78,6 +79,13 @@ message UnshareReplicaRequest {
   string uuid = 1;  // uuid of the replica
 }
 
+// Resize(expand or shrink) a replica. Only valid for normal lvol
+// replicas, and not lvols that are a snapshot.
+message ResizeReplicaRequest {
+  string uuid = 1;  // uuid of the replica.
+  uint64 requested_size = 2; // indicates the requested new size of replica.
+}
+
 // List of replicas and their properties.
 message ListReplicasResponse {
   repeated Replica replicas = 1;  // list of the replicas
diff --git a/apis/io-engine/src/v1.rs b/apis/io-engine/src/v1.rs
index d14bd35..5c991e6 100644
--- a/apis/io-engine/src/v1.rs
+++ b/apis/io-engine/src/v1.rs
@@ -55,7 +55,8 @@ pub mod replica {
         replica_rpc_client::ReplicaRpcClient,
         replica_rpc_server::{ReplicaRpc, ReplicaRpcServer},
         CreateReplicaRequest, DestroyReplicaRequest, ListReplicaOptions, ListReplicasResponse,
-        Replica, ReplicaSpaceUsage, ShareReplicaRequest, SnapshotInfo, UnshareReplicaRequest,
+        Replica, ReplicaSpaceUsage, ResizeReplicaRequest, ShareReplicaRequest, SnapshotInfo,
+        UnshareReplicaRequest,
     };
 }
 pub mod snapshot {