diff --git a/Makefile b/Makefile
index 9114fda54..9eabcc9ea 100644
--- a/Makefile
+++ b/Makefile
@@ -311,8 +311,8 @@ install-gometalinter:
 	GO111MODULE=off go get github.com/remyoudompheng/go-misc/deadcode
 
 test-txstore-rbf:
-	PILOSA_TXSRC=rbf $(MAKE) testv-race
+	PILOSA_STORAGE_BACKEND=rbf $(MAKE) testv-race
 
 test-txstore-rbf_bolt:
-	PILOSA_TXSRC=rbf_bolt $(MAKE) testv-race
+	PILOSA_STORAGE_BACKEND=rbf_bolt $(MAKE) testv-race
 
diff --git a/cluster_internal_test.go b/cluster_internal_test.go
index ea391b52d..f6f40af04 100644
--- a/cluster_internal_test.go
+++ b/cluster_internal_test.go
@@ -138,6 +138,22 @@ func TestFragCombos(t *testing.T) {
 	}
 }
 
+// newHolderWithTempPath returns a new instance of Holder.
+func newHolderWithTempPath(tb testing.TB, backend string) *Holder {
+	path, err := testhook.TempDirInDir(tb, *TempDir, "pilosa-holder-")
+	if err != nil {
+		panic(err)
+	}
+	cfg := mustHolderConfig()
+	cfg.StorageConfig.Backend = backend
+	h := NewHolder(path, cfg)
+	panicOn(h.Open())
+	testhook.Cleanup(tb, func() {
+		h.Close()
+	})
+	return h
+}
+
 // newIndexWithTempPath returns a new instance of Index.
 func newIndexWithTempPath(tb testing.TB, name string) *Index {
 	path, err := testhook.TempDirInDir(tb, *TempDir, "pilosa-index-")
diff --git a/ctl/server.go b/ctl/server.go
index c72f7d379..0d814cb86 100644
--- a/ctl/server.go
+++ b/ctl/server.go
@@ -102,11 +102,6 @@ func BuildServerFlags(cmd *cobra.Command, srv *server.Command) {
 	flags.IntVar(&srv.Config.Profile.BlockRate, "profile.block-rate", srv.Config.Profile.BlockRate, "Sampling rate for goroutine blocking profiler. One sample per <rate> ns.")
 	flags.IntVar(&srv.Config.Profile.MutexFraction, "profile.mutex-fraction", srv.Config.Profile.MutexFraction, "Sampling fraction for mutex contention profiling. Sample 1/<rate> of events.")
 
-	// Transactional storage engine
-	// Note: the default for --tx must be kept "" empty string. Otherwise we
-	// cannot detect and honor the PILOSA_TXSRC env var over-ride.
-	flags.StringVarP(&srv.Config.Txsrc, "txsrc", "", "", fmt.Sprintf("transaction/storage to use: one of roaring, rbf, bolt, or a blue-green setup: rbf_roaring, roaring_rbf, bolt_roaring, roaring_bolt, bolt_rbf, etc. The default is: %v. The env var PILOSA_TXSRC is over-ridden by --txsrc option on the command line.", storage.DefaultBackend))
-
 	// Storage
 	// Note: the default for --storage.backend must be kept "" empty string.
 	// Otherwise we cannot detect and honor the PILOSA_STORAGE_BACKEND env var
diff --git a/ctl/server_test.go b/ctl/server_test.go
index 81f49a5fd..b99a2ed25 100644
--- a/ctl/server_test.go
+++ b/ctl/server_test.go
@@ -35,14 +35,3 @@ func TestBuildServerFlags(t *testing.T) {
 		t.Fatal("log-path flag is required")
 	}
 }
-
-func TestServerDefaultTxsrcFlags(t *testing.T) {
-	cm := &cobra.Command{}
-	buf := bytes.Buffer{}
-	stdin, stdout, stderr := GetIO(buf)
-	Server := server.NewCommand(stdin, stdout, stderr)
-	BuildServerFlags(cm, Server)
-	if cm.Flags().Lookup("txsrc").DefValue != "" {
-		t.Fatal("cannot set the txsrc default in ctl/server.go, otherwise we won't know to let the environment override the lack of --txsrc on the command line. We want explicit command line --txsrc to override the env value.")
-	}
-}
diff --git a/dbshard.go b/dbshard.go
index d08f06b87..3cd3bfceb 100644
--- a/dbshard.go
+++ b/dbshard.go
@@ -925,7 +925,7 @@ func listDirUnderDir(root string, includeRoot bool, requiredSuffix string, ignor
 // The blue is the destination -- this is always types[0].
 // The green source is always types[1]. The mnemonic is blue_geen.
 // The blue is first, so it is in types[0]. The green
-// is second, in types[1]. For example, with PILOSA_TXSRC=bolt_roaring
+// is second, in types[1]. For example, with PILOSA_STORAGE_BACKEND=bolt_roaring
 // we have bolt as blue, and roaring as green. The contents of
 // bolt must be empty or exactly match roaring. If bolt
 // starts empty, it will be populated from roaring by
diff --git a/dbshard_internal_test.go b/dbshard_internal_test.go
index 18858485c..cbc3d7aaa 100644
--- a/dbshard_internal_test.go
+++ b/dbshard_internal_test.go
@@ -71,13 +71,9 @@ func TestShardPerDB_SetBit(t *testing.T) {
 
 // test that we find all *local* shards
 func Test_DBPerShard_GetShardsForIndex_LocalOnly(t *testing.T) {
-
 	tmpdir, err := ioutil.TempDir("", "Test_DBPerShard_GetShardsForIndex_LocalOnly")
 	panicOn(err)
 
-	orig := os.Getenv("PILOSA_TXSRC")
-	defer os.Setenv("PILOSA_TXSRC", orig) // must restore or will mess up other tests!
-
 	v2s := NewFieldView2Shards()
 	stdShardSet := newShardSet()
 	for _, shard := range []uint64{93, 223, 221, 215, 219, 217} {
@@ -88,11 +84,9 @@ func Test_DBPerShard_GetShardsForIndex_LocalOnly(t *testing.T) {
 	}
 
 	for _, src := range []string{"roaring", "bolt", "rbf"} {
-
-		os.Setenv("PILOSA_TXSRC", src)
-
-		// must make Holder AFTER setting src.
-		holder := NewHolder(tmpdir, nil)
+		cfg := mustHolderConfig()
+		cfg.StorageConfig.Backend = src
+		holder := NewHolder(tmpdir, cfg)
 
 		index := "rick"
 		idx := makeSampleRoaringDir(tmpdir, index, src, 1, holder, v2s)
@@ -216,7 +210,6 @@ rick.index.txstores@@@/store-rbfdb@@/shard.0223-rbfdb@
 }
 
 func makeSampleRoaringDir(root, index, txsrc string, minBytes int, h *Holder, view2shards *FieldView2Shards) (idx *Index) {
-
 	shards := []uint64{0, 93, 215, 217, 219, 221, 223}
 	fns := strings.Split(sampleRoaringDirList[txsrc], "\n")
 	firstDone := false
@@ -328,13 +321,9 @@ func Test_DBPerShard_GetFieldView2Shards_map_from_RBF(t *testing.T) {
 	tmpdir, err := ioutil.TempDir("", "Test_DBPerShard_GetFieldView2Shards_map_from_RBF")
 	panicOn(err)
 
-	orig := os.Getenv("PILOSA_TXSRC")
-	defer os.Setenv("PILOSA_TXSRC", orig) // must restore or will mess up other tests!
-
-	os.Setenv("PILOSA_TXSRC", "rbf")
-
-	// must make Holder AFTER setting src.
-	holder := NewHolder(tmpdir, nil)
+	cfg := mustHolderConfig()
+	cfg.StorageConfig.Backend = "rbf"
+	holder := NewHolder(tmpdir, cfg)
 	defer holder.Close()
 
 	index := "rick"
diff --git a/executor_test.go b/executor_test.go
index 8c5323303..66fb91b27 100644
--- a/executor_test.go
+++ b/executor_test.go
@@ -25,7 +25,6 @@ import (
 	"io/ioutil"
 	"math"
 	"math/rand"
-	"os"
 	"reflect"
 	"strconv"
 	"strings"
@@ -539,7 +538,7 @@ func TestExecutor_Execute_Count(t *testing.T) {
 }
 
 func roaringOnlyTest(t *testing.T) {
-	src := os.Getenv("PILOSA_TXSRC")
+	src := pilosa.CurrentBackend()
 	if src == pilosa.RoaringTxn || (storage.DefaultBackend == pilosa.RoaringTxn && src == "") {
 		// okay to run, we are under roaring only
 	} else {
diff --git a/fragment_internal_test.go b/fragment_internal_test.go
index 780a6d0b7..093b5e7aa 100644
--- a/fragment_internal_test.go
+++ b/fragment_internal_test.go
@@ -1720,7 +1720,7 @@ func TestFragment_RankCache_Persistence(t *testing.T) {
 }
 
 func roaringOnlyTest(t *testing.T) {
-	src := os.Getenv("PILOSA_TXSRC")
+	src := CurrentBackend()
 	if src == RoaringTxn || (storage.DefaultBackend == RoaringTxn && src == "") {
 		// okay to run, we are under roaring only
 	} else {
@@ -1729,7 +1729,7 @@ func roaringOnlyTest(t *testing.T) {
 }
 
 func roaringOnlyBenchmark(b *testing.B) {
-	src := os.Getenv("PILOSA_TXSRC")
+	src := CurrentBackend()
 	if src == RoaringTxn || (storage.DefaultBackend == RoaringTxn && src == "") {
 		// okay to run, we are under roaring only
 	} else {
@@ -3574,7 +3574,7 @@ func mustOpenBSIFragment(tb testing.TB, index, field, view string, shard uint64)
 
 func newTestHolder(tb testing.TB) *Holder {
 	path, _ := testhook.TempDirInDir(tb, *TempDir, "holder-dir")
-	h := NewHolder(path, nil)
+	h := NewHolder(path, mustHolderConfig())
 	panicOn(h.Open())
 	testhook.Cleanup(tb, func() {
 		h.Close()
@@ -5530,8 +5530,7 @@ func TestFragment_Bug_Q2DoubleDelete(t *testing.T) {
 }
 
 func notBlueGreenTest(t *testing.T) {
-	src := os.Getenv("PILOSA_TXSRC")
-	if strings.Contains(src, "_") {
+	if strings.Contains(CurrentBackend(), "_") {
 		t.Skip("skip under blue green")
 	}
 }
diff --git a/holder.go b/holder.go
index 21b4ada8e..9fd37703d 100644
--- a/holder.go
+++ b/holder.go
@@ -242,13 +242,6 @@ func DefaultHolderConfig() *HolderConfig {
 func NewHolder(path string, cfg *HolderConfig) *Holder {
 	if cfg == nil {
 		cfg = DefaultHolderConfig()
-		// still want the PILOSA_TXSRC to override, for tests use.
-		txsrc := os.Getenv("PILOSA_TXSRC")
-		if txsrc != "" {
-			_ = MustTxsrcToTxtype(txsrc)
-			// INVAR: have valid txsrc.
-			cfg.StorageConfig.Backend = txsrc
-		}
 	}
 	if cfg.StorageConfig == nil {
 		cfg.StorageConfig = storage.NewDefaultConfig()
diff --git a/holder_internal_test.go b/holder_internal_test.go
index 1db02a8b0..6ed4a63a6 100644
--- a/holder_internal_test.go
+++ b/holder_internal_test.go
@@ -76,12 +76,16 @@ func (t *testHolderOperator) ProcessFragment(*fragment) error {
 	return nil
 }
 
-func makeHolder(tb testing.TB) (*Holder, string, error) {
+func makeHolder(tb testing.TB, backend string) (*Holder, string, error) {
 	path, err := testhook.TempDir(tb, "pilosa-")
 	if err != nil {
 		return nil, "", err
 	}
-	h := NewHolder(path, nil)
+	cfg := mustHolderConfig()
+	if backend != "" {
+		cfg.StorageConfig.Backend = backend
+	}
+	h := NewHolder(path, cfg)
 	return h, path, h.Open()
 }
 
@@ -170,7 +174,7 @@ func testHasBit(t *testing.T, h *Holder, index, field string, rowID, columnID ui
 }
 
 func TestHolderOperatorProcess(t *testing.T) {
-	h, path, err := makeHolder(t)
+	h, path, err := makeHolder(t, "")
 	if err != nil {
 		t.Fatalf("creating holder: %v", err)
 	}
@@ -200,7 +204,7 @@ func TestHolderOperatorProcess(t *testing.T) {
 }
 
 func TestHolderOperatorCancel(t *testing.T) {
-	h, path, err := makeHolder(t)
+	h, path, err := makeHolder(t, "")
 	if err != nil {
 		t.Fatalf("creating holder: %v", err)
 	}
@@ -247,3 +251,17 @@ func TestHolderOperatorCancel(t *testing.T) {
 		t.Fatalf("holder processor did not cancel. expected something other than %#v", expected)
 	}
 }
+
+// mustHolderConfig is meant to help minimize the number of places in the code
+// where we're reading the PILOSA_STORAGE_BACKEND environment variable for
+// testing purposes. Ideally we would handle this differently, but this is a
+// first attempt at improving things. Note: the actual os.Getenv() call was
+// moved to the CurrentBackend() function.
+func mustHolderConfig() *HolderConfig {
+	cfg := DefaultHolderConfig()
+	if backend := CurrentBackend(); backend != "" {
+		_ = MustTxsrcToTxtype(backend)
+		cfg.StorageConfig.Backend = backend
+	}
+	return cfg
+}
diff --git a/http/handler.go b/http/handler.go
index 49e3b1efa..316f5cec9 100644
--- a/http/handler.go
+++ b/http/handler.go
@@ -820,8 +820,7 @@ func (h *Handler) handlePostQuery(w http.ResponseWriter, r *http.Request) {
 	req, ok := qreq.(*pilosa.QueryRequest)
 
 	if DoPerQueryProfiling {
-
-		txsrc := os.Getenv("PILOSA_TXSRC")
+		txsrc := pilosa.CurrentBackend()
 		reqHash := hash(req.Query)
 
 		qlen := len(req.Query)
@@ -839,13 +838,6 @@ func (h *Handler) handlePostQuery(w http.ResponseWriter, r *http.Request) {
 		defer pprof.StopCPUProfile()
 
 	} // end DoPerQueryProfiling
-	/*
-		er = trace.Start(f)
-		if er != nil {
-			panic(er)
-		}
-		defer trace.Stop()
-	*/
 
 	var err error
 	err, _ = qerr.(error)
diff --git a/pilosa.go b/pilosa.go
index edb0240d1..39c98f34f 100644
--- a/pilosa.go
+++ b/pilosa.go
@@ -16,6 +16,7 @@ package pilosa
 
 import (
 	"encoding/json"
+	"os"
 	"regexp"
 	"time"
 
@@ -215,3 +216,11 @@ func AddressWithDefaults(addr string) (*pnet.URI, error) {
 	}
 	return pnet.NewURIFromAddress(addr)
 }
+
+// CurrentBackend is one step in an attempt to centralize (and either minimize
+// or completely remove), the calls to environment variables throughout the
+// tests. Ideally we could get rid of this and rely completely on the
+// configuration parameters.
+func CurrentBackend() string {
+	return os.Getenv("PILOSA_STORAGE_BACKEND")
+}
diff --git a/pprof.go b/pprof.go
index a13ef62d2..2fd9768af 100644
--- a/pprof.go
+++ b/pprof.go
@@ -31,7 +31,7 @@ import (
 // commented out—in holder.go.
 func CPUProfileForDur(dur time.Duration, outpath string) {
 	// per-query pprof output:
-	txsrc := os.Getenv("PILOSA_TXSRC")
+	txsrc := CurrentBackend()
 	if txsrc == "" {
 		txsrc = storage.DefaultBackend
 	}
@@ -57,7 +57,7 @@ func CPUProfileForDur(dur time.Duration, outpath string) {
 // commented out—in holder.go.
 func MemProfileForDur(dur time.Duration, outpath string) {
 	// per-query pprof output:
-	txsrc := os.Getenv("PILOSA_TXSRC")
+	txsrc := CurrentBackend()
 	if txsrc == "" {
 		txsrc = storage.DefaultBackend
 	}
diff --git a/rrtx_internal_test.go b/rrtx_internal_test.go
index a993b25b4..7ceefe6c9 100644
--- a/rrtx_internal_test.go
+++ b/rrtx_internal_test.go
@@ -15,17 +15,14 @@
 package pilosa
 
 import (
-	"os"
 	"testing"
 )
 
 func TestRoaring_HasData(t *testing.T) {
+	holder := newHolderWithTempPath(t, "roaring")
 
-	orig := os.Getenv("PILOSA_TXSRC")
-	defer os.Setenv("PILOSA_TXSRC", orig) // must restore or will mess up other tests!
-	os.Setenv("PILOSA_TXSRC", "roaring")
-
-	idx := newIndexWithTempPath(t, "i")
+	idx, err := holder.CreateIndex("i", IndexOptions{})
+	panicOn(err)
 	defer idx.Close()
 
 	db, err := globalRoaringReg.OpenDBWrapper(idx.path, false, nil)
diff --git a/server/cluster_test.go b/server/cluster_test.go
index 75878f493..9108771ac 100644
--- a/server/cluster_test.go
+++ b/server/cluster_test.go
@@ -20,7 +20,6 @@ import (
 	"fmt"
 	"net"
 	"net/http"
-	"os"
 	"reflect"
 	"strings"
 	"testing"
@@ -144,9 +143,9 @@ func TestClusterResize_AddNode(t *testing.T) {
 	// Why are we skipping this test under blue-green with Roaring?
 	//
 	// We see red test: during resize during importRoaringBits
-	// PILOSA_TXSRC=rbf_roaring go test -v  -tags=' shardwidth20'  "-gcflags=all=-d=checkptr=0" -run TestClusterResize_AddNode/"ContinuousShards"
+	// PILOSA_STORAGE_BACKEND=rbf_roaring go test -v  -tags=' shardwidth20'  "-gcflags=all=-d=checkptr=0" -run TestClusterResize_AddNode/"ContinuousShards"
 	// green:
-	// PILOSA_TXSRC=roaring_rbf go test -v  -tags=' shardwidth20'  "-gcflags=all=-d=checkptr=0" -run TestClusterResize_AddNode/"ContinuousShards"
+	// PILOSA_STORAGE_BACKEND=roaring_rbf go test -v  -tags=' shardwidth20'  "-gcflags=all=-d=checkptr=0" -run TestClusterResize_AddNode/"ContinuousShards"
 	//
 	// but rbf_badger and badger_rbf are both green (use the same data values for containers).
 	//
@@ -807,7 +806,7 @@ func TestClusterMutualTLS(t *testing.T) {
 }
 
 func skipTestUnderBlueGreenWithRoaring(t *testing.T) {
-	src := os.Getenv("PILOSA_TXSRC")
+	src := pilosa.CurrentBackend()
 	if strings.Contains(src, "_") {
 		if strings.Contains(src, "roaring") {
 			t.Skip("skip for roaring blue-green")
diff --git a/server/config.go b/server/config.go
index 920320d97..f374e5db2 100644
--- a/server/config.go
+++ b/server/config.go
@@ -194,19 +194,17 @@ type Config struct {
 		ConnectionLimit uint16 `toml:"max-connections"`
 	} `toml:"postgres"`
 
-	// Txsrc determines which Tx implementation the holder/Index will use; one
-	// of the available transactional-storage engines. Choices are listed
-	// in the string constants below. Should be one of
-	// "roaring","bolt", "rbf", "bolt_roaring", "roaring_bolt", "rbf_roaring",
-	// "roaring_rbf", "bolt_rbf", "rbf_bolt", or any later addition. The
-	// engines with _ underscore indicate use of a blueGreenTx with a comparison
-	// of values back from each Tx method, and a panic if they differ. This
-	// is an effective test for consistency. If "rbf_roaring" is specified, then
-	// the roaring values are the ones actually returned from the blueGreenTx.
-	// If "roaring_rbf" is chosen, then the RBF values are the ones actually
+	// Storage.Backend determines which Tx implementation the holder/Index will
+	// use; one of the available transactional-storage engines. Choices are
+	// listed in the string constants below. Should be one of "roaring","bolt",
+	// "rbf", "bolt_roaring", "roaring_bolt", "rbf_roaring", "roaring_rbf",
+	// "bolt_rbf", "rbf_bolt", or any later addition. The engines with _
+	// underscore indicate use of a blueGreenTx with a comparison of values back
+	// from each Tx method, and a panic if they differ. This is an effective
+	// test for consistency. If "rbf_roaring" is specified, then the roaring
+	// values are the ones actually returned from the blueGreenTx. If
+	// "roaring_rbf" is chosen, then the RBF values are the ones actually
 	// returned from the blueGreenTx.
-	Txsrc string `toml:"txsrc"`
-
 	Storage *storage.Config `toml:"storage"`
 
 	// RowcacheOn, if true, turns on the row cache for all storage backends.
diff --git a/server/server.go b/server/server.go
index 702f57b30..0839db450 100644
--- a/server/server.go
+++ b/server/server.go
@@ -55,7 +55,6 @@ import (
 	"github.com/pilosa/pilosa/v2/statik"
 	"github.com/pilosa/pilosa/v2/stats"
 	"github.com/pilosa/pilosa/v2/statsd"
-	"github.com/pilosa/pilosa/v2/storage"
 	"github.com/pilosa/pilosa/v2/syswrap"
 	"github.com/pilosa/pilosa/v2/testhook"
 	"github.com/pkg/errors"
@@ -283,32 +282,6 @@ func (m *Command) SetupServer() error {
 
 	m.logger.Printf("%s", pilosa.VersionInfo())
 
-	// If the pilosa command line uses -tx to override the
-	// PILOSA_TXSRC env variable, then we must also correct
-	// the environment, so that pilosa/txfactory.go can determine the
-	// desired Tx engine. This enables "go test" testing in pilosa that
-	// does not spin up a full server, while still respecting the pilosa
-	// server's choice when run full in production.
-	envTxsrc := os.Getenv("PILOSA_TXSRC")
-	if m.Config.Txsrc == "" {
-		// INVAR: No -tx flag on the command line.
-		// We defer to the environment, and then the DefaultBackend
-		if envTxsrc == "" {
-			// no env variable requested either.
-			m.Config.Txsrc = storage.DefaultBackend
-		} else {
-			// Tell the "regular" prod server what to use.
-			m.Config.Txsrc = envTxsrc
-		}
-	}
-	// INVAR: m.Config.Storage.Backend is valid and not "", but storage.DefaultBackend could be bad.
-	txty := pilosa.MustTxsrcToTxtype(m.Config.Storage.Backend) // will panic on unknown Backend.
-	os.Setenv("PILOSA_TXSRC", m.Config.Txsrc)
-	m.logger.Printf("using Txsrc '%v'/%v", m.Config.Txsrc, txty)
-	if len(txty) == 2 {
-		m.logger.Printf("blue='%v' / green='%v'", txty[0], txty[1])
-	}
-
 	// validateAddrs sets the appropriate values for Bind and Advertise
 	// based on the inputs. It is not responsible for applying defaults, although
 	// it does provide a non-zero port (10101) in the case where no port is specified.
diff --git a/stattx.go b/stattx.go
index 8004e795f..68e97f7c6 100644
--- a/stattx.go
+++ b/stattx.go
@@ -18,7 +18,6 @@ import (
 	"fmt"
 	"io"
 	"math"
-	"os"
 	"runtime"
 	"sort"
 	"sync"
@@ -70,7 +69,7 @@ func (w *callStats) reset() {
 }
 
 func (c *callStats) report() (r string) {
-	txsrc := os.Getenv("PILOSA_TXSRC")
+	txsrc := CurrentBackend()
 	r = fmt.Sprintf("callStats: (%v)\n", txsrc)
 	c.mu.Lock()
 	defer c.mu.Unlock()
diff --git a/test/cluster.go b/test/cluster.go
index 22714739f..e085ee790 100644
--- a/test/cluster.go
+++ b/test/cluster.go
@@ -30,6 +30,7 @@ import (
 	"github.com/pilosa/pilosa/v2/api/client"
 	"github.com/pilosa/pilosa/v2/proto"
 	"github.com/pilosa/pilosa/v2/server"
+	"github.com/pilosa/pilosa/v2/storage"
 	"github.com/pilosa/pilosa/v2/test/port"
 	"github.com/pkg/errors"
 	"golang.org/x/sync/errgroup"
@@ -446,7 +447,6 @@ func newCluster(tb testing.TB, size int, opts ...[]server.CommandOption) (*Clust
 // MustRunCluster creates and starts a new cluster. The opts parameter
 // is slightly magical; see MustNewCluster.
 func MustRunCluster(tb testing.TB, size int, opts ...[]server.CommandOption) *Cluster {
-
 	cluster := MustNewCluster(tb, size, opts...)
 	err := cluster.Start()
 	if err != nil {
@@ -481,7 +481,14 @@ func prependOpts(opts [][]server.CommandOption, size int) [][]server.CommandOpti
 // prependTestServerOpts prepends opts with the OpenInMemTranslateStore.
 func prependTestServerOpts(opts []server.CommandOption) []server.CommandOption {
 	defaultOpts := []server.CommandOption{
-		server.OptCommandServerOptions(pilosa.OptServerOpenTranslateStore(pilosa.OpenInMemTranslateStore), pilosa.OptServerNodeDownRetries(5, 100*time.Millisecond)),
+		server.OptCommandServerOptions(
+			pilosa.OptServerOpenTranslateStore(pilosa.OpenInMemTranslateStore),
+			pilosa.OptServerNodeDownRetries(5, 100*time.Millisecond),
+			pilosa.OptServerStorageConfig(&storage.Config{
+				Backend:      pilosa.CurrentBackend(),
+				FsyncEnabled: true,
+			}),
+		),
 	}
 	return append(defaultOpts, opts...)
 }
diff --git a/test/pilosa.go b/test/pilosa.go
index b5335ca23..e999a3cd3 100644
--- a/test/pilosa.go
+++ b/test/pilosa.go
@@ -70,12 +70,6 @@ func newCommand(tb testing.TB, opts ...server.CommandOption) *Command {
 	m.Config.DataDir = path
 	defaultConf := server.NewConfig()
 
-	// TODO: this is temporary and should be removed and
-	// automatically replaced with PILOSA_STORAGE_BACKEND.
-	if txsrc := os.Getenv("PILOSA_TXSRC"); txsrc != "" {
-		m.Config.Storage.Backend = txsrc
-	}
-
 	if m.Config.Bind == defaultConf.Bind {
 		m.Config.Bind = "http://localhost:0"
 	}
diff --git a/tournament.sh b/tournament.sh
index 793ef7231..1729ef167 100755
--- a/tournament.sh
+++ b/tournament.sh
@@ -1,13 +1,13 @@
 #!/bin/bash
 
 ## tournament.sh runs a sequence of duels between greens and blues.
-## Each test run changes the PILOSA_TXSRC and runs either
+## Each test run changes the PILOSA_STORAGE_BACKEND and runs either
 ## one or two backends through the rigors of make testv-race.
 ## logs are saved to the tourna.log.${i} files.
 
 for i in rbf roaring bolt rbf_roaring roaring_rbf roaring_bolt; do
    echo "$(date) starting ${i}, output to tourna.log.${i}"
    echo "***=== ${i} ====================*** $(date)" &> tourna.log.${i}
-   PILOSA_TXSRC=${i}  make testv-race 2>&1 > tourna.log.${i}
+   PILOSA_STORAGE_BACKEND=${i}  make testv-race 2>&1 > tourna.log.${i}
 done
 
diff --git a/tx_test.go b/tx_test.go
index b942651b2..00bec7e7a 100644
--- a/tx_test.go
+++ b/tx_test.go
@@ -17,7 +17,6 @@ package pilosa_test
 import (
 	"context"
 	"fmt"
-	"os"
 	"strings"
 	"testing"
 
@@ -61,7 +60,7 @@ func queryBalances(m0api *pilosa.API, acctOwnerID uint64, fldAcct0, fldAcct1, in
 }
 
 func skipForRoaring(t *testing.T) {
-	src := os.Getenv("PILOSA_TXSRC")
+	src := pilosa.CurrentBackend()
 	// once txfactory.go storage.DefaultBackend != RoaringTxn, this
 	// will break, of course. Take out the src == "" below.
 	if (src == "" && storage.DefaultBackend == pilosa.RoaringTxn) || strings.Contains(src, "roaring") {
diff --git a/txfactory.go b/txfactory.go
index 818bb8ac3..84281d63e 100644
--- a/txfactory.go
+++ b/txfactory.go
@@ -1284,7 +1284,7 @@ func (f *TxFactory) greenHasData() (hasData bool, err error) {
 // Called by test Test_TxFactory_UpdateBlueFromGreen_OnStartup() in
 // txfactory_internal_test.go as well.
 //
-// This is a noop if we aren't running under a blue_green PILOSA_TXSRC.
+// This is a noop if we aren't running under a blue_green PILOSA_STORAGE_BACKEND.
 func (f *TxFactory) green2blue(holder *Holder) (err0 error) {
 
 	// Holder.Open will always call us, even without blue_green. Which is fine.
diff --git a/txfactory_internal_test.go b/txfactory_internal_test.go
index 7a71243d4..f3299b14f 100644
--- a/txfactory_internal_test.go
+++ b/txfactory_internal_test.go
@@ -23,7 +23,7 @@ import (
 )
 
 func Test_TxFactory_Qcx_query_context(t *testing.T) {
-	src := os.Getenv("PILOSA_TXSRC")
+	src := CurrentBackend()
 	if src == "rbf" || src == "bolt" {
 		// ok
 	} else {
@@ -114,10 +114,6 @@ func Test_TxFactory_Qcx_query_context(t *testing.T) {
 //       and b) we have an easy migration mechanism, to go from one storage format to another.
 //
 func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
-
-	orig := os.Getenv("PILOSA_TXSRC")
-	defer os.Setenv("PILOSA_TXSRC", orig) // must restore or will mess up other tests!
-
 	checked := []string{"roaring", "rbf"}
 
 	expectError := false
@@ -140,8 +136,7 @@ func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
 			//
 			// Setup happens with green only.
 
-			os.Setenv("PILOSA_TXSRC", green)
-			h, path, err := makeHolder(t)
+			h, path, err := makeHolder(t, green)
 			if err != nil {
 				t.Fatalf("creating holder: %v", err)
 			}
@@ -179,7 +174,7 @@ func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
 			testMustHaveBit(t, h, "i1", "f", 100, 200)
 			testMustHaveBit(t, h, "i1", "f", 100, 12345678)
 
-			//vv("about to reopen; blue_green = '%v' but PILOSA_TXSRC='%v'", blue_green, os.Getenv("PILOSA_TXSRC"))
+			//vv("about to reopen; blue_green = '%v' but PILOSA_STORAGE_BACKEND='%v'", blue_green, os.Getenv("PILOSA_STORAGE_BACKEND"))
 			//h.DumpAllShards()
 
 			//vv("after dump, about to close")
@@ -190,7 +185,7 @@ func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
 			// can we re.Open the same holder h? hopefully without a problem.
 			panicOn(h.Open())
 
-			//vv("h.Open() re-open worked; blue_green = '%v'; dump; with PILOSA_TXSRC='%v'", blue_green, os.Getenv("PILOSA_TXSRC"))
+			//vv("h.Open() re-open worked; blue_green = '%v'; dump; with PILOSA_STORAGE_BACKEND='%v'", blue_green, os.Getenv("PILOSA_STORAGE_BACKEND"))
 			//h.DumpAllShards()
 
 			testMustHaveBit(t, h, "i0", "f", rowID, colID) // panic here, colID 200 bit was cold.
@@ -202,7 +197,9 @@ func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
 
 			// check that we can open a NewHolder on green, on same path, and still see our bits.
 			// Because the NewHolder is the code that creates and configures TxFactory as blue_green.
-			h2 := NewHolder(path, nil)
+			cfg := mustHolderConfig()
+			cfg.StorageConfig.Backend = green
+			h2 := NewHolder(path, cfg)
 			panicOn(h2.Open())
 
 			testMustHaveBit(t, h2, "i0", "f", rowID, colID)
@@ -212,9 +209,9 @@ func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
 
 			// verify that blue does not have it.
 			// open a new holder on path, just looking at blue.
-			os.Setenv("PILOSA_TXSRC", blue)
-
-			h3 := NewHolder(path, nil)
+			cfg = mustHolderConfig()
+			cfg.StorageConfig.Backend = blue
+			h3 := NewHolder(path, cfg)
 			panicOn(h3.Open())
 
 			testMustNotHaveBit(t, h3, "i0", "f", rowID, colID)
@@ -232,11 +229,11 @@ func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
 			// Since blue is empty, the blue database will get synched up
 			// with the green during Holder.Open().
 
-			os.Setenv("PILOSA_TXSRC", blue_green)
-
 			// open a holder with path again, now looking at both blue and green.
 			// The Holder.Open should do the migration from green, populating blue.
-			h4 := NewHolder(path, nil)
+			cfg = mustHolderConfig()
+			cfg.StorageConfig.Backend = blue_green
+			h4 := NewHolder(path, cfg)
 
 			//vv("about to h4.Open we should populate blue from green")
 			err = h4.Open()
@@ -263,10 +260,6 @@ func Test_TxFactory_UpdateBlueFromGreen_OnStartup(t *testing.T) {
 // go to verify it but blue has more data than green.
 // That will also cause query divergence.
 func Test_TxFactory_verifyBlueEqualsGreen(t *testing.T) {
-
-	orig := os.Getenv("PILOSA_TXSRC")
-	defer os.Setenv("PILOSA_TXSRC", orig) // must restore or will mess up other tests!
-
 	checked := []string{"roaring", "bolt", "rbf"}
 
 	for _, blue := range checked {
@@ -285,8 +278,7 @@ func Test_TxFactory_verifyBlueEqualsGreen(t *testing.T) {
 			//
 			// Setup happens with green only.
 
-			os.Setenv("PILOSA_TXSRC", green)
-			h, path, err := makeHolder(t)
+			h, path, err := makeHolder(t, green)
 			if err != nil {
 				t.Fatalf("creating holder: %v", err)
 			}
@@ -328,11 +320,12 @@ func Test_TxFactory_verifyBlueEqualsGreen(t *testing.T) {
 
 			// verify that blue does not have it.
 			// open a new holder on path, just looking at blue.
-			os.Setenv("PILOSA_TXSRC", blue)
 
 			//vv("on blue, which is '%v'", blue)
 
-			h3 := NewHolder(path, nil)
+			cfg := mustHolderConfig()
+			cfg.StorageConfig.Backend = blue
+			h3 := NewHolder(path, cfg)
 			panicOn(h3.Open())
 
 			testMustNotHaveBit(t, h3, "i0", "f", rowID, colID)
@@ -350,13 +343,13 @@ func Test_TxFactory_verifyBlueEqualsGreen(t *testing.T) {
 			// Since blue is empty, the blue database will get synched up
 			// with the green during Holder.Open().
 
-			os.Setenv("PILOSA_TXSRC", blue_green)
-
 			//vv("on blue_green, which is '%v'", blue_green)
 
 			// open a holder with path again, now looking at both blue and green.
 			// The Holder.Open should do the migration from green, populating blue.
-			h4 := NewHolder(path, nil)
+			cfg = mustHolderConfig()
+			cfg.StorageConfig.Backend = blue_green
+			h4 := NewHolder(path, cfg)
 			panicOn(h4.Open())
 
 			testMustHaveBit(t, h4, "i0", "f", rowID, colID)
@@ -365,11 +358,10 @@ func Test_TxFactory_verifyBlueEqualsGreen(t *testing.T) {
 			h4.Close()
 
 			// now open just blue, and add a bit to a new index, i2.
-			os.Setenv("PILOSA_TXSRC", blue)
-
 			//vv("on blue, which is '%v'", blue)
-
-			h5 := NewHolder(path, nil)
+			cfg = mustHolderConfig()
+			cfg.StorageConfig.Backend = blue
+			h5 := NewHolder(path, cfg)
 			panicOn(h5.Open())
 			testSetBit(t, h5, "i2", "f", 500, 777)
 
@@ -380,13 +372,14 @@ func Test_TxFactory_verifyBlueEqualsGreen(t *testing.T) {
 
 			// now open blue_green. should get a verification failure
 			// due to the extra bit in blue.
-			os.Setenv("PILOSA_TXSRC", blue_green)
 
 			// BEGIN verficiation that should ERROR out b/c blue has more data.
 
 			// open a holder with path again, now looking at both blue and green.
 			// The Holder.Open should verify blue against green and notice the extra bit.
-			h6 := NewHolder(path, nil)
+			cfg = mustHolderConfig()
+			cfg.StorageConfig.Backend = blue_green
+			h6 := NewHolder(path, cfg)
 			err = h6.Open()
 			//h6.DumpAllShards()