diff --git a/lib/nvme/nvme_ctrlr.c b/lib/nvme/nvme_ctrlr.c
index de2d50638..f100140c7 100644
--- a/lib/nvme/nvme_ctrlr.c
+++ b/lib/nvme/nvme_ctrlr.c
@@ -54,6 +54,20 @@ static void nvme_ctrlr_init_cap(struct spdk_nvme_ctrlr *ctrlr);
 static void nvme_ctrlr_set_state(struct spdk_nvme_ctrlr *ctrlr, enum nvme_ctrlr_state state,
 				 uint64_t timeout_in_ms);
 
+static int
+nvme_ns_cmp(struct spdk_nvme_ns *ns1, struct spdk_nvme_ns *ns2)
+{
+	if (ns1->id < ns2->id) {
+		return -1;
+	} else if (ns1->id > ns2->id) {
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+RB_GENERATE_STATIC(nvme_ns_tree, spdk_nvme_ns, node, nvme_ns_cmp);
+
 #define CTRLR_STRING(ctrlr) \
 	((ctrlr->trid.trtype == SPDK_NVME_TRANSPORT_TCP || ctrlr->trid.trtype == SPDK_NVME_TRANSPORT_RDMA) ? \
 	ctrlr->trid.subnqn : ctrlr->trid.traddr)
@@ -2206,17 +2220,14 @@ nvme_active_ns_ctx_destroy(struct nvme_active_ns_ctx *ctx)
 static int
 nvme_ctrlr_destruct_namespace(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid)
 {
-	struct spdk_nvme_ns *ns;
+	struct spdk_nvme_ns tmp, *ns;
 
 	assert(ctrlr != NULL);
 
-	if (nsid < 1 || nsid > ctrlr->num_ns) {
-		return -EINVAL;
-	}
-
-	ns = ctrlr->ns[nsid - 1];
+	tmp.id = nsid;
+	ns = RB_FIND(nvme_ns_tree, &ctrlr->ns, &tmp);
 	if (ns == NULL) {
-		return 0;
+		return -EINVAL;
 	}
 
 	nvme_ns_destruct(ns);
@@ -2996,18 +3007,15 @@ nvme_ctrlr_set_host_id(struct spdk_nvme_ctrlr *ctrlr)
 static void
 nvme_ctrlr_destruct_namespaces(struct spdk_nvme_ctrlr *ctrlr)
 {
-	if (ctrlr->ns) {
-		uint32_t i, num_ns = ctrlr->num_ns;
+	struct spdk_nvme_ns *ns, *tmp_ns;
 
-		for (i = 1; i <= num_ns; i++) {
-			nvme_ctrlr_destruct_namespace(ctrlr, i);
-			spdk_free(ctrlr->ns[i - 1]);
-		}
-
-		spdk_free(ctrlr->ns);
-		ctrlr->ns = NULL;
-		ctrlr->num_ns = 0;
+	RB_FOREACH_SAFE(ns, nvme_ns_tree, &ctrlr->ns, tmp_ns) {
+		nvme_ctrlr_destruct_namespace(ctrlr, ns->id);
+		RB_REMOVE(nvme_ns_tree, &ctrlr->ns, ns);
+		spdk_free(ns);
 	}
+
+	ctrlr->num_ns = 0;
 }
 
 void
@@ -3026,45 +3034,15 @@ nvme_ctrlr_update_namespaces(struct spdk_nvme_ctrlr *ctrlr)
 static int
 nvme_ctrlr_construct_namespaces(struct spdk_nvme_ctrlr *ctrlr)
 {
-	int rc = 0;
-	uint32_t i, nn = ctrlr->cdata.nn;
-	struct spdk_nvme_ns **tmp;
 	struct spdk_nvme_ns *ns;
 
-	/* ctrlr->num_ns may be 0 (startup) or a different number of namespaces (reset),
-	 * so check if we need to reallocate.
-	 */
-	if (nn != ctrlr->num_ns) {
+	ctrlr->num_ns = ctrlr->cdata.nn;
 
-		tmp = spdk_realloc(ctrlr->ns, nn * sizeof(struct spdk_nvme_ns *), 64);
-
-		if (tmp == NULL) {
-			rc = -ENOMEM;
-			goto fail;
-		}
-
-		if (nn > ctrlr->num_ns) {
-			memset(tmp + ctrlr->num_ns, 0, (nn - ctrlr->num_ns) * sizeof(struct spdk_nvme_ns *));
-		}
-
-		ctrlr->ns = tmp;
-		ctrlr->num_ns = nn;
-	}
-
-	for (i = 0; i < ctrlr->num_ns; i++) {
-		ns = ctrlr->ns[i];
-		if (ns != NULL) {
-			nvme_ns_free_iocs_specific_data(ns);
-		}
+	RB_FOREACH(ns, nvme_ns_tree, &ctrlr->ns) {
+		nvme_ns_free_iocs_specific_data(ns);
 	}
 
 	return 0;
-
-fail:
-	nvme_ctrlr_destruct_namespaces(ctrlr);
-	NVME_CTRLR_ERRLOG(ctrlr, "Failed to construct namespaces, err %d\n", rc);
-	nvme_ctrlr_set_state(ctrlr, NVME_CTRLR_STATE_ERROR, NVME_TIMEOUT_INFINITE);
-	return rc;
 }
 
 static int
@@ -4146,6 +4124,8 @@ nvme_ctrlr_construct(struct spdk_nvme_ctrlr *ctrlr)
 	TAILQ_INIT(&ctrlr->active_procs);
 	STAILQ_INIT(&ctrlr->register_operations);
 
+	RB_INIT(&ctrlr->ns);
+
 	return rc;
 }
 
@@ -4492,6 +4472,7 @@ spdk_nvme_ctrlr_get_next_active_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t prev_
 struct spdk_nvme_ns *
 spdk_nvme_ctrlr_get_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid)
 {
+	struct spdk_nvme_ns tmp;
 	struct spdk_nvme_ns *ns;
 
 	if (nsid < 1 || nsid > ctrlr->num_ns) {
@@ -4500,7 +4481,8 @@ spdk_nvme_ctrlr_get_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid)
 
 	nvme_robust_mutex_lock(&ctrlr->ctrlr_lock);
 
-	ns = ctrlr->ns[nsid - 1];
+	tmp.id = nsid;
+	ns = RB_FIND(nvme_ns_tree, &ctrlr->ns, &tmp);
 
 	if (ns == NULL) {
 		ns = spdk_zmalloc(sizeof(struct spdk_nvme_ns), 64, NULL, SPDK_ENV_SOCKET_ID_ANY, SPDK_MALLOC_SHARE);
@@ -4510,7 +4492,8 @@ spdk_nvme_ctrlr_get_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid)
 		}
 
 		NVME_CTRLR_DEBUGLOG(ctrlr, "Namespace %u was added\n", nsid);
-		ctrlr->ns[nsid - 1] = ns;
+		ns->id = nsid;
+		RB_INSERT(nvme_ns_tree, &ctrlr->ns, ns);
 	}
 
 	nvme_robust_mutex_unlock(&ctrlr->ctrlr_lock);
diff --git a/lib/nvme/nvme_internal.h b/lib/nvme/nvme_internal.h
index 27d6b735b..a41e3ca6a 100644
--- a/lib/nvme/nvme_internal.h
+++ b/lib/nvme/nvme_internal.h
@@ -54,6 +54,7 @@
 #include "spdk/memory.h"
 #include "spdk/nvme_intel.h"
 #include "spdk/nvmf_spec.h"
+#include "spdk/tree.h"
 #include "spdk/uuid.h"
 
 #include "spdk_internal/assert.h"
@@ -532,6 +533,8 @@ struct spdk_nvme_ns {
 
 	/* Zoned Namespace Command Set Specific Identify Namespace data. */
 	struct spdk_nvme_zns_ns_data	*nsdata_zns;
+
+	RB_ENTRY(spdk_nvme_ns)		node;
 };
 
 /**
@@ -857,8 +860,8 @@ struct nvme_register_completion {
 struct spdk_nvme_ctrlr {
 	/* Hot data (accessed in I/O path) starts here. */
 
-	/** Array of namespace pointers indexed by nsid - 1 */
-	struct spdk_nvme_ns		**ns;
+	/* Tree of namespaces */
+	RB_HEAD(nvme_ns_tree, spdk_nvme_ns)	ns;
 
 	uint32_t			num_ns;
 
diff --git a/test/unit/lib/nvme/nvme_ctrlr.c/nvme_ctrlr_ut.c b/test/unit/lib/nvme/nvme_ctrlr.c/nvme_ctrlr_ut.c
index 0a254fa0e..b851890cd 100644
--- a/test/unit/lib/nvme/nvme_ctrlr.c/nvme_ctrlr_ut.c
+++ b/test/unit/lib/nvme/nvme_ctrlr.c/nvme_ctrlr_ut.c
@@ -2103,8 +2103,7 @@ test_nvme_ctrlr_test_active_ns(void)
 		ctrlr.vs.bits.ter = 0;
 		ctrlr.cdata.nn = 1531;
 
-		ctrlr.ns = calloc(ctrlr.cdata.nn, sizeof(struct spdk_nvme_ns *));
-		SPDK_CU_ASSERT_FATAL(ctrlr.ns != NULL);
+		RB_INIT(&ctrlr.ns);
 		ctrlr.num_ns = ctrlr.cdata.nn;
 
 		nvme_ctrlr_identify_active_ns(&ctrlr);
@@ -2145,7 +2144,6 @@ test_nvme_ctrlr_test_active_ns(void)
 		for (nsid = 0; nsid < ctrlr.num_ns; nsid++) {
 			ctrlr.active_ns_list[nsid] = nsid + 1;
 		}
-		ctrlr.active_ns_list[ctrlr.active_ns_count] = 0;
 
 		ns_id_count = 0;
 		for (nsid = spdk_nvme_ctrlr_get_first_active_ns(&ctrlr);
@@ -2901,22 +2899,22 @@ test_nvme_ctrlr_identify_namespaces_iocs_specific_next(void)
 	uint32_t prev_nsid;
 	uint32_t active_ns_list[5] = {1, 2, 3, 4, 5};
 	struct spdk_nvme_ns ns[5] = {};
-	struct spdk_nvme_ns *ns_array[5];
 	struct spdk_nvme_ctrlr ns_ctrlr[5] = {};
 	int rc = 0;
 	int i;
 
+	RB_INIT(&ctrlr.ns);
 	for (i = 0; i < 5; i++) {
-		ns_array[i] = &ns[i];
+		ns[i].id = i + 1;
+		RB_INSERT(nvme_ns_tree, &ctrlr.ns, &ns[i]);
 	}
 
-	ctrlr.ns = ns_array;
 	ctrlr.cdata.nn = 5;
-	ctrlr.active_ns_count = 5;
 	ctrlr.num_ns = 5;
 	/* case 1: No first/next active NS, move on to the next state, expect: pass */
 	prev_nsid = 0;
 	ctrlr.active_ns_list = NULL;
+	ctrlr.active_ns_count = 0;
 	ctrlr.opts.admin_timeout_ms = NVME_TIMEOUT_INFINITE;
 	rc = nvme_ctrlr_identify_namespaces_iocs_specific_next(&ctrlr, prev_nsid);
 	CU_ASSERT(rc == 0);
@@ -2928,6 +2926,7 @@ test_nvme_ctrlr_identify_namespaces_iocs_specific_next(void)
 	memset(&ctrlr.state_timeout_tsc, 0x00, sizeof(ctrlr.state_timeout_tsc));
 	prev_nsid = 1;
 	ctrlr.active_ns_list = active_ns_list;
+	ctrlr.active_ns_count = 5;
 	ns[1].csi = SPDK_NVME_CSI_NVM;
 	ns[1].id = 2;
 	rc = nvme_ctrlr_identify_namespaces_iocs_specific_next(&ctrlr, prev_nsid);
@@ -2941,6 +2940,7 @@ test_nvme_ctrlr_identify_namespaces_iocs_specific_next(void)
 	ctrlr.opts.admin_timeout_ms = NVME_TIMEOUT_INFINITE;
 	prev_nsid = 0;
 	ctrlr.active_ns_list = active_ns_list;
+	ctrlr.active_ns_count = 5;
 
 	for (int i = 0; i < 5; i++) {
 		ns[i].csi = SPDK_NVME_CSI_NVM;
@@ -2966,6 +2966,7 @@ test_nvme_ctrlr_identify_namespaces_iocs_specific_next(void)
 	memset(&ctrlr.state_timeout_tsc, 0x00, sizeof(ctrlr.state_timeout_tsc));
 	prev_nsid = 1;
 	ctrlr.active_ns_list = active_ns_list;
+	ctrlr.active_ns_count = 5;
 	ns[1].csi = SPDK_NVME_CSI_ZNS;
 	g_fail_next_identify = true;
 	rc = nvme_ctrlr_identify_namespaces_iocs_specific_next(&ctrlr, prev_nsid);
@@ -3037,17 +3038,17 @@ test_nvme_ctrlr_parse_ana_log_page(void)
 	int rc, i;
 	struct spdk_nvme_ctrlr ctrlr = {};
 	struct spdk_nvme_ns ns[3] = {};
-	struct spdk_nvme_ns *ns_array[3];
 	struct spdk_nvme_ana_page ana_hdr;
 	char _ana_desc[UT_ANA_DESC_SIZE];
 	struct spdk_nvme_ana_group_descriptor *ana_desc;
 	uint32_t offset;
 
+	RB_INIT(&ctrlr.ns);
 	for (i = 0; i < 3; i++) {
-		ns_array[i] = &ns[i];
+		ns[i].id = i + 1;
+		RB_INSERT(nvme_ns_tree, &ctrlr.ns, &ns[i]);
 	}
 
-	ctrlr.ns = ns_array;
 	ctrlr.cdata.nn = 3;
 	ctrlr.cdata.nanagrpid = 3;
 	ctrlr.num_ns = 3;
diff --git a/test/unit/lib/nvme/nvme_ctrlr_cmd.c/nvme_ctrlr_cmd_ut.c b/test/unit/lib/nvme/nvme_ctrlr_cmd.c/nvme_ctrlr_cmd_ut.c
index 80d0ff5b5..dec7cb492 100644
--- a/test/unit/lib/nvme/nvme_ctrlr_cmd.c/nvme_ctrlr_cmd_ut.c
+++ b/test/unit/lib/nvme/nvme_ctrlr_cmd.c/nvme_ctrlr_cmd_ut.c
@@ -79,6 +79,14 @@ DEFINE_STUB(nvme_transport_qpair_iterate_requests, int,
 DEFINE_STUB(nvme_qpair_abort_queued_reqs_with_cbarg, uint32_t,
 	    (struct spdk_nvme_qpair *qpair, void *cmd_cb_arg), 0);
 
+static int
+nvme_ns_cmp(struct spdk_nvme_ns *ns1, struct spdk_nvme_ns *ns2)
+{
+	return ns1->id - ns2->id;
+}
+
+RB_GENERATE_STATIC(nvme_ns_tree, spdk_nvme_ns, node, nvme_ns_cmp);
+
 static void verify_firmware_log_page(struct nvme_request *req)
 {
 	uint32_t temp_cdw10;
@@ -373,13 +381,15 @@ static struct spdk_nvme_ns g_inactive_ns = {};
 struct spdk_nvme_ns *
 spdk_nvme_ctrlr_get_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid)
 {
+	struct spdk_nvme_ns tmp;
 	struct spdk_nvme_ns *ns;
 
 	if (nsid < 1 || nsid > ctrlr->num_ns) {
 		return NULL;
 	}
 
-	ns = ctrlr->ns[nsid - 1];
+	tmp.id = nsid;
+	ns = RB_FIND(nvme_ns_tree, &ctrlr->ns, &tmp);
 
 	if (ns == NULL) {
 		return &g_inactive_ns;
diff --git a/test/unit/lib/nvme/nvme_ctrlr_ocssd_cmd.c/nvme_ctrlr_ocssd_cmd_ut.c b/test/unit/lib/nvme/nvme_ctrlr_ocssd_cmd.c/nvme_ctrlr_ocssd_cmd_ut.c
index 31f5c0fd5..3ef28f3b5 100644
--- a/test/unit/lib/nvme/nvme_ctrlr_ocssd_cmd.c/nvme_ctrlr_ocssd_cmd_ut.c
+++ b/test/unit/lib/nvme/nvme_ctrlr_ocssd_cmd.c/nvme_ctrlr_ocssd_cmd_ut.c
@@ -59,18 +59,28 @@ verify_request_fn_t verify_fn;
 
 static const uint32_t expected_geometry_ns = 1;
 
+static int
+nvme_ns_cmp(struct spdk_nvme_ns *ns1, struct spdk_nvme_ns *ns2)
+{
+	return ns1->id - ns2->id;
+}
+
+RB_GENERATE_STATIC(nvme_ns_tree, spdk_nvme_ns, node, nvme_ns_cmp);
+
 static struct spdk_nvme_ns g_inactive_ns = {};
 
 struct spdk_nvme_ns *
 spdk_nvme_ctrlr_get_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid)
 {
+	struct spdk_nvme_ns tmp;
 	struct spdk_nvme_ns *ns;
 
 	if (nsid < 1 || nsid > ctrlr->num_ns) {
 		return NULL;
 	}
 
-	ns = ctrlr->ns[nsid - 1];
+	tmp.id = nsid;
+	ns = RB_FIND(nvme_ns_tree, &ctrlr->ns, &tmp);
 
 	if (ns == NULL) {
 		return &g_inactive_ns;
@@ -121,13 +131,13 @@ test_spdk_nvme_ctrlr_is_ocssd_supported(void)
 {
 	struct spdk_nvme_ctrlr ctrlr = {};
 	struct spdk_nvme_ns ns = {};
-	struct spdk_nvme_ns *ns_array;
 	bool rc;
 
-	ns_array = &ns;
+	RB_INIT(&ctrlr.ns);
+	ns.id = 1;
+	RB_INSERT(nvme_ns_tree, &ctrlr.ns, &ns);
 
 	ns.nsdata.vendor_specific[0] = 1;
-	ctrlr.ns = &ns_array;
 	ctrlr.quirks |= NVME_QUIRK_OCSSD;
 	ctrlr.cdata.vid = SPDK_PCI_VID_CNEXLABS;
 	ctrlr.num_ns = 1;
diff --git a/test/unit/lib/nvme/nvme_cuse.c/nvme_cuse_ut.c b/test/unit/lib/nvme/nvme_cuse.c/nvme_cuse_ut.c
index c34b2411e..8257c9927 100644
--- a/test/unit/lib/nvme/nvme_cuse.c/nvme_cuse_ut.c
+++ b/test/unit/lib/nvme/nvme_cuse.c/nvme_cuse_ut.c
@@ -85,6 +85,14 @@ DEFINE_STUB(pthread_join, int, (pthread_t tid, void **val), 0);
 
 DEFINE_STUB_V(nvme_ctrlr_update_namespaces, (struct spdk_nvme_ctrlr *ctrlr));
 
+static int
+nvme_ns_cmp(struct spdk_nvme_ns *ns1, struct spdk_nvme_ns *ns2)
+{
+	return ns1->id - ns2->id;
+}
+
+RB_GENERATE_STATIC(nvme_ns_tree, spdk_nvme_ns, node, nvme_ns_cmp);
+
 struct cuse_io_ctx *g_ut_ctx;
 struct spdk_nvme_ctrlr *g_ut_ctrlr;
 uint32_t g_ut_nsid;
@@ -135,13 +143,15 @@ static struct spdk_nvme_ns g_inactive_ns = {};
 struct spdk_nvme_ns *
 spdk_nvme_ctrlr_get_ns(struct spdk_nvme_ctrlr *ctrlr, uint32_t nsid)
 {
+	struct spdk_nvme_ns tmp;
 	struct spdk_nvme_ns *ns;
 
 	if (nsid < 1 || nsid > ctrlr->num_ns) {
 		return NULL;
 	}
 
-	ns = ctrlr->ns[nsid - 1];
+	tmp.id = nsid;
+	ns = RB_FIND(nvme_ns_tree, &ctrlr->ns, &tmp);
 
 	if (ns == NULL) {
 		return &g_inactive_ns;
@@ -291,7 +301,6 @@ test_cuse_nvme_submit_io(void)
 	struct spdk_nvme_ctrlr ctrlr = {};
 	struct fuse_file_info fi = {};
 	struct spdk_nvme_ns ns = {};
-	struct spdk_nvme_ns *ns_array;
 	struct nvme_user_io *user_io = NULL;
 	char arg[1024] = {};
 	fuse_req_t req = (void *)0xDEEACDFF;
@@ -300,10 +309,11 @@ test_cuse_nvme_submit_io(void)
 	user_io = calloc(3, 4096);
 	SPDK_CU_ASSERT_FATAL(user_io != NULL);
 
-	ns_array = &ns;
+	RB_INIT(&ctrlr.ns);
+	ns.id = 1;
+	RB_INSERT(nvme_ns_tree, &ctrlr.ns, &ns);
 
 	cuse_device.ctrlr = &ctrlr;
-	ctrlr.ns = &ns_array;
 	ctrlr.num_ns = 1;
 	ns.sector_size = 4096;
 	ns.id = 1;