diff --git a/server/opts.go b/server/opts.go
index d3184e70..43b798dd 100644
--- a/server/opts.go
+++ b/server/opts.go
@@ -185,7 +185,9 @@ type Options struct {
 	Gateway               GatewayOpts   `json:"gateway,omitempty"`
 	LeafNode              LeafNodeOpts  `json:"leaf,omitempty"`
 	JetStream             bool          `json:"jetstream"`
-	StoreDir              string        `json:"store_dir"`
+	JetStreamMaxMemory    int64         `json:"-"`
+	JetStreamMaxStore     int64         `json:"-"`
+	StoreDir              string        `json:"-"`
 	ProfPort              int           `json:"-"`
 	PidFile               string        `json:"-"`
 	PortsFileDir          string        `json:"-"`
@@ -1145,6 +1147,10 @@ func parseJetStream(v interface{}, opts *Options, errors *[]error, warnings *[]e
 		switch strings.ToLower(mk) {
 		case "store_dir", "storedir":
 			opts.StoreDir = mv.(string)
+		case "max_memory_store", "max_mem_store":
+			opts.JetStreamMaxMemory = mv.(int64)
+		case "max_file_store":
+			opts.JetStreamMaxStore = mv.(int64)
 		default:
 			if !tk.IsUsedVariable() {
 				err := &unknownConfigFieldErr{
diff --git a/server/server.go b/server/server.go
index 5b03a179..17997d05 100644
--- a/server/server.go
+++ b/server/server.go
@@ -24,6 +24,8 @@ import (
 	"math/rand"
 	"net"
 	"net/http"
+	// Allow dynamic profiling.
+	_ "net/http/pprof"
 	"os"
 	"path"
 	"path/filepath"
@@ -34,12 +36,10 @@ import (
 	"sync/atomic"
 	"time"
 
-	// Allow dynamic profiling.
-	_ "net/http/pprof"
-
 	"github.com/nats-io/jwt"
-	"github.com/nats-io/nats-server/v2/logger"
 	"github.com/nats-io/nkeys"
+
+	"github.com/nats-io/nats-server/v2/logger"
 )
 
 const (
@@ -1260,7 +1260,11 @@ func (s *Server) Start() {
 	if opts.JetStream {
 		var cfg *JetStreamConfig
 		if opts.StoreDir != "" {
-			cfg = &JetStreamConfig{StoreDir: opts.StoreDir}
+			cfg = &JetStreamConfig{
+				StoreDir:  opts.StoreDir,
+				MaxMemory: opts.JetStreamMaxMemory,
+				MaxStore:  opts.JetStreamMaxStore,
+			}
 		}
 		if err := s.EnableJetStream(cfg); err != nil {
 			s.Fatalf("Can't start jetstream: %v", err)