diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d315cb9ac3..48a78f65776 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@
 - [#8525](https://github.com/influxdata/influxdb/issues/8525): Support http pipelining for /query endpoint.
 - [#8652](https://github.com/influxdata/influxdb/pull/8652): Reduce allocations when reading data
 - [#8592](https://github.com/influxdata/influxdb/pull/8592): Mutex profiles are now available.
+- [#8669](https://github.com/influxdata/influxdb/pull/8669): TSI Index Migration Tool
 
 ### Bugfixes
 
diff --git a/cmd/influx_inspect/help/help.go b/cmd/influx_inspect/help/help.go
index 3610fe43d49..3b66ad25b39 100644
--- a/cmd/influx_inspect/help/help.go
+++ b/cmd/influx_inspect/help/help.go
@@ -34,6 +34,7 @@ The commands are:
     dumptsi              dumps low-level details about tsi1 files.
     dumptsm              dumps low-level details about tsm1 files.
     export               exports raw data from a shard to line protocol
+    inmem2tsi            generates a tsi1 index from an in-memory index shard
     help                 display this help message
     report               displays a shard level report
     verify               verifies integrity of TSM files
diff --git a/cmd/influx_inspect/inmem2tsi/inmem2tsi.go b/cmd/influx_inspect/inmem2tsi/inmem2tsi.go
new file mode 100644
index 00000000000..70c742fe52d
--- /dev/null
+++ b/cmd/influx_inspect/inmem2tsi/inmem2tsi.go
@@ -0,0 +1,164 @@
+// Package inmem2tsi reads an in-memory index and exports it as a TSI index.
+package inmem2tsi
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/influxdata/influxdb/models"
+	"github.com/influxdata/influxdb/tsdb"
+	"github.com/influxdata/influxdb/tsdb/index/inmem"
+	"github.com/influxdata/influxdb/tsdb/index/tsi1"
+	"github.com/uber-go/zap"
+)
+
+// Command represents the program execution for "influx_inspect inmem2tsi".
+type Command struct {
+	Stderr io.Writer
+	Stdout io.Writer
+	Logger zap.Logger
+}
+
+// NewCommand returns a new instance of Command.
+func NewCommand() *Command {
+	return &Command{
+		Stderr: os.Stderr,
+		Stdout: os.Stdout,
+		Logger: zap.New(zap.NullEncoder()),
+	}
+}
+
+// Run executes the command.
+func (cmd *Command) Run(args ...string) error {
+	fs := flag.NewFlagSet("inmem2tsi", flag.ExitOnError)
+	path := fs.String("path", "", "data path")
+	walPath := fs.String("wal-path", "", "WAL path")
+	verbose := fs.Bool("v", false, "verbose")
+	fs.SetOutput(cmd.Stdout)
+	fs.Usage = cmd.printUsage
+	if err := fs.Parse(args); err != nil {
+		return err
+	} else if fs.NArg() > 0 || *path == "" || *walPath == "" {
+		cmd.printUsage()
+		return flag.ErrHelp
+	}
+
+	if *verbose {
+		cmd.Logger = zap.New(
+			zap.NewTextEncoder(),
+			zap.Output(os.Stderr),
+		)
+	}
+
+	return cmd.run(*path, *walPath, *verbose)
+}
+
+func (cmd *Command) run(path, walPath string, verbose bool) error {
+	// Check if shard already has a TSI index.
+	indexPath := filepath.Join(path, "index")
+	cmd.Logger.Info("checking index path", zap.String("path", indexPath))
+	if _, err := os.Stat(indexPath); !os.IsNotExist(err) {
+		return errors.New("tsi1 index already exists")
+	}
+
+	cmd.Logger.Info("opening shard", zap.String("path", path), zap.String("wal-path", walPath))
+
+	// Open shard at path.
+	sh := tsdb.NewShard(0, path, walPath, tsdb.EngineOptions{
+		EngineVersion: tsdb.DefaultEngine,
+		IndexVersion:  inmem.IndexName,
+		InmemIndex:    inmem.NewIndex(""),
+	})
+	if err := sh.Open(); err != nil {
+		return err
+	}
+	defer sh.CloseFast()
+
+	cmd.Logger.Info("reading in-memory index")
+
+	// Retrieve in-memory index reference.
+	inmemIndex, ok := sh.Index().(*inmem.ShardIndex)
+	if !ok {
+		return fmt.Errorf("invalid source index type: %T", sh.Index())
+	}
+
+	// Remove temporary index files if this is being re-run.
+	tmpPath := filepath.Join(path, ".index")
+	cmd.Logger.Info("cleaning up partial index from previous run, if any")
+	if err := os.RemoveAll(tmpPath); err != nil {
+		return err
+	}
+
+	// Open TSI index in temporary path.
+	tsiIndex := tsi1.NewIndex()
+	tsiIndex.Path = tmpPath
+	tsiIndex.WithLogger(cmd.Logger)
+	cmd.Logger.Info("opening tsi index in temporary location", zap.String("path", tmpPath))
+	if err := tsiIndex.Open(); err != nil {
+		return err
+	}
+	defer tsiIndex.Close()
+
+	cmd.Logger.Info("iterating over measurements")
+
+	// Iterate over each series & insert into new index.
+	if err := inmemIndex.ForEachMeasurementName(func(name []byte) error {
+		cmd.Logger.Info("processing measurement", zap.String("name", string(name)))
+
+		mm, err := inmemIndex.Measurement(name)
+		if err != nil {
+			return err
+		} else if mm == nil {
+			return nil
+		}
+
+		if err := mm.ForEachSeriesByExpr(nil, func(tags models.Tags) error {
+			cmd.Logger.Info("series", zap.String("name", string(name)), zap.String("tags", tags.String()))
+			if err := tsiIndex.CreateSeriesIfNotExists(nil, name, tags); err != nil {
+				return fmt.Errorf("cannot create series: %s %s (%s)", name, tags.String(), err)
+			}
+			return nil
+		}); err != nil {
+			return err
+		}
+		return nil
+
+	}); err != nil {
+		return err
+	}
+
+	cmd.Logger.Info("compacting index")
+
+	// Attempt to compact the index & wait for all compactions to complete.
+	tsiIndex.Compact()
+	tsiIndex.Wait()
+
+	cmd.Logger.Info("closing tsi index")
+
+	// Close TSI index.
+	if err := tsiIndex.Close(); err != nil {
+		return err
+	}
+
+	cmd.Logger.Info("moving tsi to permanent location")
+
+	// Rename TSI to standard path.
+	if err := os.Rename(tmpPath, indexPath); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (cmd *Command) printUsage() {
+	usage := `Converts a shard from an in-memory index to a TSI index.
+
+Usage: influx_inspect inmem2tsi -path DATA_PATH -wal-path WAL_PATH
+`
+
+	fmt.Fprintf(cmd.Stdout, usage)
+}
diff --git a/cmd/influx_inspect/main.go b/cmd/influx_inspect/main.go
index 8f2434ed595..82b82a4118f 100644
--- a/cmd/influx_inspect/main.go
+++ b/cmd/influx_inspect/main.go
@@ -12,6 +12,7 @@ import (
 	"github.com/influxdata/influxdb/cmd/influx_inspect/dumptsm"
 	"github.com/influxdata/influxdb/cmd/influx_inspect/export"
 	"github.com/influxdata/influxdb/cmd/influx_inspect/help"
+	"github.com/influxdata/influxdb/cmd/influx_inspect/inmem2tsi"
 	"github.com/influxdata/influxdb/cmd/influx_inspect/report"
 	"github.com/influxdata/influxdb/cmd/influx_inspect/verify"
 	_ "github.com/influxdata/influxdb/tsdb/engine"
@@ -72,6 +73,11 @@ func (m *Main) Run(args ...string) error {
 		if err := name.Run(args...); err != nil {
 			return fmt.Errorf("export: %s", err)
 		}
+	case "inmem2tsi":
+		name := inmem2tsi.NewCommand()
+		if err := name.Run(args...); err != nil {
+			return fmt.Errorf("inmem2tsi: %s", err)
+		}
 	case "report":
 		name := report.NewCommand()
 		if err := name.Run(args...); err != nil {
diff --git a/tsdb/index/tsi1/index.go b/tsdb/index/tsi1/index.go
index 0b32008c8bf..090b753888d 100644
--- a/tsdb/index/tsi1/index.go
+++ b/tsdb/index/tsi1/index.go
@@ -242,6 +242,11 @@ func (i *Index) deleteNonManifestFiles(m *Manifest) error {
 	return nil
 }
 
+// Wait returns once outstanding compactions have finished.
+func (i *Index) Wait() {
+	i.wg.Wait()
+}
+
 // Close closes the index.
 func (i *Index) Close() error {
 	// Wait for goroutines to finish.
diff --git a/tsdb/shard.go b/tsdb/shard.go
index c5a8b1c51a0..5c15512b7b6 100644
--- a/tsdb/shard.go
+++ b/tsdb/shard.go
@@ -401,6 +401,12 @@ func (s *Shard) UnloadIndex() {
 	s.index.RemoveShard(s.id)
 }
 
+// Index returns a reference to the underlying index.
+// This should only be used by utilities and not directly accessed by the database.
+func (s *Shard) Index() Index {
+	return s.index
+}
+
 // IsIdle return true if the shard is not receiving writes and is fully compacted.
 func (s *Shard) IsIdle() bool {
 	if err := s.ready(); err != nil {