diff --git a/src/object/srv_obj_migrate.c b/src/object/srv_obj_migrate.c
index 854d03f5ead..7c6c85ba81d 100644
--- a/src/object/srv_obj_migrate.c
+++ b/src/object/srv_obj_migrate.c
@@ -32,10 +32,10 @@
 #endif
 
 /* Max in-flight transfer size per xstream */
-/* Set the total in-flight size to be 50% of MAX DMA size for
+/* Set the total in-flight size to be 1/3 of MAX DMA size for
  * the moment, will adjust it later if needed.
  */
-#define MIGR_TGT_INF_DATA       (1 << 29)
+#define MIGR_TGT_INF_DATA       (300 << 20)
 
 /* Threshold for very large transfers.
  * This may exceed the MIGR_TGT_INF_DATA limit to prevent starvation.
@@ -51,10 +51,10 @@
 
 /* Number of migration ULTs per target */
 #define MIGR_TGT_ULTS_MIN       100
-#define MIGR_TGT_ULTS_DEF       500
-#define MIGR_TGT_ULTS_MAX       2000
+#define MIGR_TGT_ULTS_DEF       300
+#define MIGR_TGT_ULTS_MAX       1000
 
-/* 1/3 object ults, 2/3 key ULTs */
+/* 1/3 object ults (100), 2/3 key ULTs (200) */
 #define MIGR_OBJ_ULT_PERCENT    33
 
 #define MIGR_TGT_OBJ_ULTS(ults) ((ults * MIGR_OBJ_ULT_PERCENT) / 100)
@@ -715,16 +715,16 @@ mrone_obj_fetch_internal(struct migrate_one *mrone, daos_handle_t oh, d_sg_list_
 		 */
 		DL_WARN(rc, DF_RB ": retry " DF_UOID, DP_RB_MPT(tls), DP_UOID(mrone->mo_oid));
 		if (rc == -DER_NOMEM) {
-			/* sleep 10 seconds before retry, give other layers a chance to
+			/* sleep a few seconds before retry, give other layers a chance to
 			 * release resources.
 			 */
-			dss_sleep(10 * 1000);
+			dss_sleep((10 + rand() % 20) * 1000);
 			if (waited != 0 && waited % 3600 == 0) {
 				DL_ERROR(rc, DF_RB ": waited memory for %d hour(s)",
 					 DP_RB_MRO(mrone), waited / 3600);
 			}
 		}
-		waited += 10;
+		waited += 20;
 		D_GOTO(retry, rc);
 	}
 
@@ -1945,12 +1945,16 @@ migrate_res_hold(struct migrate_pool_tls *tls, int res_type, long units, bool *y
 		*yielded = waited;
 
 	/* per-pool counters for rebuild status tracking */
-	if (res_type == MIGR_OBJ)
+	if (res_type == MIGR_OBJ) {
 		tls->mpt_tgt_obj_ult_cnt++;
-	else if (res_type == MIGR_KEY)
+	} else if (res_type == MIGR_KEY) {
 		tls->mpt_tgt_dkey_ult_cnt++;
-	else
+	} else {
 		tls->mpt_inflight_size += units;
+		/* remaining resource may be sufficient for more waiters */
+		if (waited && res->res_units < res->res_limit)
+			ABT_cond_signal(res->res_cond);
+	}
 
 	D_DEBUG(DB_REBUILD,
 		"res=%s, hold=%lu, used=%lu, limit=%lu, waited=%d)\n" DF_RB
@@ -2010,6 +2014,7 @@ migrate_one_ult(void *arg)
 	struct migrate_one      *mrone = arg;
 	struct migrate_pool_tls	*tls;
 	daos_size_t		data_size;
+	daos_size_t              degraded_size = 0;
 	int			rc = 0;
 
 	while (daos_fail_check(DAOS_REBUILD_TGT_REBUILD_HANG))
@@ -2022,21 +2027,35 @@ migrate_one_ult(void *arg)
 	}
 
 	data_size = daos_iods_len(mrone->mo_iods, mrone->mo_iod_num);
-	data_size += daos_iods_len(mrone->mo_iods_from_parity,
-				   mrone->mo_iods_num_from_parity);
+	data_size += daos_iods_len(mrone->mo_iods_from_parity, mrone->mo_iods_num_from_parity);
+	if (daos_oclass_is_ec(&mrone->mo_oca)) {
+		/* NB: this is a workaround for EC object:
+		 * The fetch buffer is taken from a pre-registered (R)DMA buffer;
+		 * however, a degraded EC read will allocate and register an extra
+		 * buffer to recover data.
+		 *
+		 * Currently, the resource manager cannot control this extra allocation,
+		 * which can lead to increased memory consumption.
+		 *
+		 * While this workaround does not prevent dynamic buffer allocation and
+		 * registration, it does provide relatively precise control over the
+		 * resources consumed by degraded EC reads.
+		 */
+		degraded_size = data_size * MIN(16, obj_ec_data_tgt_nr(&mrone->mo_oca));
+	}
 
 	D_DEBUG(DB_TRACE, DF_RB ": mrone %p data size is " DF_U64 " %d/%d\n", DP_RB_MPT(tls), mrone,
 		data_size, mrone->mo_iod_num, mrone->mo_iods_num_from_parity);
 
 	D_ASSERT(data_size != (daos_size_t)-1);
 
-	rc = migrate_res_hold(tls, MIGR_DATA, data_size, NULL);
+	rc = migrate_res_hold(tls, MIGR_DATA, data_size + degraded_size, NULL);
 	if (rc)
 		D_GOTO(out, rc);
 
 	rc = migrate_dkey(tls, mrone, data_size);
 
-	migrate_res_release(tls, MIGR_DATA, data_size);
+	migrate_res_release(tls, MIGR_DATA, data_size + degraded_size);
 
 	D_DEBUG(DB_REBUILD,
 		DF_RB ": " DF_UOID " layout %u migrate dkey " DF_KEY " inflight_size " DF_U64