diff --git a/cmd/lotus-miner/sectors.go b/cmd/lotus-miner/sectors.go
index 4d241b282..968e92174 100644
--- a/cmd/lotus-miner/sectors.go
+++ b/cmd/lotus-miner/sectors.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
 	"os"
 	"sort"
 	"strconv"
@@ -2056,7 +2057,6 @@ func yesno(b bool) string {
 	return color.RedString("NO")
 }
 
-// TODO simulate this call if --really-do-it is not used
 var sectorsCompactPartitionsCmd = &cli.Command{
 	Name:  "compact-partitions",
 	Usage: "removes dead sectors from partitions and reduces the number of partitions used if possible",
@@ -2082,12 +2082,7 @@ var sectorsCompactPartitionsCmd = &cli.Command{
 		},
 	},
 	Action: func(cctx *cli.Context) error {
-		if !cctx.Bool("really-do-it") {
-			fmt.Println("Pass --really-do-it to actually execute this action")
-			return nil
-		}
-
-		api, acloser, err := lcli.GetFullNodeAPI(cctx)
+		fullNodeAPI, acloser, err := lcli.GetFullNodeAPI(cctx)
 		if err != nil {
 			return err
 		}
@@ -2100,7 +2095,7 @@ var sectorsCompactPartitionsCmd = &cli.Command{
 			return err
 		}
 
-		minfo, err := api.StateMinerInfo(ctx, maddr, types.EmptyTSK)
+		minfo, err := fullNodeAPI.StateMinerInfo(ctx, maddr, types.EmptyTSK)
 		if err != nil {
 			return err
 		}
@@ -2116,46 +2111,118 @@ var sectorsCompactPartitionsCmd = &cli.Command{
 		}
 		fmt.Printf("compacting %d paritions\n", len(parts))
 
+		var makeMsgForPartitions func(partitionsBf bitfield.BitField) ([]*types.Message, error)
+		makeMsgForPartitions = func(partitionsBf bitfield.BitField) ([]*types.Message, error) {
+			params := miner.CompactPartitionsParams{
+				Deadline:   deadline,
+				Partitions: partitionsBf,
+			}
+
+			sp, aerr := actors.SerializeParams(&params)
+			if aerr != nil {
+				return nil, xerrors.Errorf("serializing params: %w", err)
+			}
+
+			msg := &types.Message{
+				From:   minfo.Worker,
+				To:     maddr,
+				Method: builtin.MethodsMiner.CompactPartitions,
+				Value:  big.Zero(),
+				Params: sp,
+			}
+
+			estimatedMsg, err := fullNodeAPI.GasEstimateMessageGas(ctx, msg, nil, types.EmptyTSK)
+			if err != nil && xerrors.Is(err, &api.ErrOutOfGas{}) {
+				// the message is too big -- split into 2
+				partitionsSlice, err := partitionsBf.All(math.MaxUint64)
+				if err != nil {
+					return nil, err
+				}
+
+				partitions1 := bitfield.New()
+				for i := 0; i < len(partitionsSlice)/2; i++ {
+					partitions1.Set(uint64(i))
+				}
+
+				msgs1, err := makeMsgForPartitions(partitions1)
+				if err != nil {
+					return nil, err
+				}
+
+				// time for the second half
+				partitions2 := bitfield.New()
+				for i := len(partitionsSlice) / 2; i < len(partitionsSlice); i++ {
+					partitions2.Set(uint64(i))
+				}
+
+				msgs2, err := makeMsgForPartitions(partitions2)
+				if err != nil {
+					return nil, err
+				}
+
+				return append(msgs1, msgs2...), nil
+			} else if err != nil {
+				return nil, err
+			}
+
+			return []*types.Message{estimatedMsg}, nil
+		}
+
 		partitions := bitfield.New()
 		for _, partition := range parts {
 			partitions.Set(uint64(partition))
 		}
 
-		params := miner.CompactPartitionsParams{
-			Deadline:   deadline,
-			Partitions: partitions,
-		}
-
-		sp, err := actors.SerializeParams(&params)
+		msgs, err := makeMsgForPartitions(partitions)
 		if err != nil {
-			return xerrors.Errorf("serializing params: %w", err)
+			return xerrors.Errorf("failed to make messages: %w", err)
 		}
 
-		smsg, err := api.MpoolPushMessage(ctx, &types.Message{
-			From:   minfo.Worker,
-			To:     maddr,
-			Method: builtin.MethodsMiner.CompactPartitions,
-			Value:  big.Zero(),
-			Params: sp,
-		}, nil)
-		if err != nil {
-			return xerrors.Errorf("mpool push: %w", err)
+		// Actually send the messages if really-do-it provided, simulate otherwise
+		if cctx.Bool("really-do-it") {
+			smsgs, err := fullNodeAPI.MpoolBatchPushMessage(ctx, msgs, nil)
+			if err != nil {
+				return xerrors.Errorf("mpool push: %w", err)
+			}
+
+			if len(smsgs) == 1 {
+				fmt.Printf("Requested compact partitions in message %s\n", smsgs[0].Cid())
+			} else {
+				fmt.Printf("Requested compact partitions in %d messages\n\n", len(smsgs))
+				for _, v := range smsgs {
+					fmt.Println(v.Cid())
+				}
+			}
+
+			for _, v := range smsgs {
+				wait, err := fullNodeAPI.StateWaitMsg(ctx, v.Cid(), 2)
+				if err != nil {
+					return err
+				}
+
+				// check it executed successfully
+				if wait.Receipt.ExitCode.IsError() {
+					fmt.Println(cctx.App.Writer, "compact partitions msg %s failed!", v.Cid())
+					return err
+				}
+			}
+
+			return nil
 		}
 
-		fmt.Printf("Requested compact partitions in message %s\n", smsg.Cid())
+		for i, v := range msgs {
+			fmt.Printf("total of %d CompactPartitions msgs would be sent\n", len(msgs))
 
-		wait, err := api.StateWaitMsg(ctx, smsg.Cid(), 0)
-		if err != nil {
-			return err
-		}
+			estMsg, err := fullNodeAPI.GasEstimateMessageGas(ctx, v, nil, types.EmptyTSK)
+			if err != nil {
+				return err
+			}
 
-		// check it executed successfully
-		if wait.Receipt.ExitCode.IsError() {
-			fmt.Println(cctx.App.Writer, "compact partitions failed!")
-			return err
+			fmt.Printf("msg %d would cost up to %s\n", i+1, types.FIL(estMsg.RequiredFunds()))
 		}
 
 		return nil
+
 	},
 }