diff --git a/chain/consensus/filcns/upgrades.go b/chain/consensus/filcns/upgrades.go
index 26c93a0f37e..c6b7a896752 100644
--- a/chain/consensus/filcns/upgrades.go
+++ b/chain/consensus/filcns/upgrades.go
@@ -6,7 +6,6 @@ import (
 	_ "embed"
 	"fmt"
 	"os"
-	"runtime"
 	"strconv"
 	"time"
 
@@ -72,7 +71,7 @@ var (
 
 func init() {
 	// the default calculation used for migration worker count
-	MigrationMaxWorkerCount = runtime.NumCPU()
+	MigrationMaxWorkerCount = 8
 	// check if an alternative value was request by environment
 	if mwcs := os.Getenv(EnvMigrationMaxWorkerCount); mwcs != "" {
 		mwc, err := strconv.ParseInt(mwcs, 10, 32)
diff --git a/chain/stmgr/forks.go b/chain/stmgr/forks.go
index 93f53c63ff0..d8d1bfb8972 100644
--- a/chain/stmgr/forks.go
+++ b/chain/stmgr/forks.go
@@ -235,7 +235,7 @@ func runPreMigration(ctx context.Context, sm *StateManager, fn PreMigrationFunc,
 	height := ts.Height()
 	parent := ts.ParentState()
 
-	if disabled := os.Getenv(EnvDisablePreMigrations); strings.TrimSpace(disabled) == "1" {
+	if val, isSet := os.LookupEnv(EnvDisablePreMigrations); !isSet || strings.TrimSpace(val) != "0" {
 		log.Warnw("SKIPPING pre-migration", "height", height)
 		return
 	}
diff --git a/chain/stmgr/forks_test.go b/chain/stmgr/forks_test.go
index bf8793488b6..531559978c4 100644
--- a/chain/stmgr/forks_test.go
+++ b/chain/stmgr/forks_test.go
@@ -377,6 +377,9 @@ func testForkRefuseCall(t *testing.T, nullsBefore, nullsAfter int) {
 func TestForkPreMigration(t *testing.T) {
 	//stm: @CHAIN_GEN_NEXT_TIPSET_001,
 	//stm: @CHAIN_STATE_RESOLVE_TO_KEY_ADDR_001, @CHAIN_STATE_SET_VM_CONSTRUCTOR_001
+	if err := os.Setenv("LOTUS_DISABLE_PRE_MIGRATIONS", "0"); err != nil {
+		t.Fatalf("failed to force LOTUS_DISABLE_PRE_MIGRATIONS: %v", err)
+	}
 	logging.SetAllLoggers(logging.LevelInfo)
 
 	cg, err := gen.NewGenerator()
diff --git a/documentation/en/default-lotus-config.toml b/documentation/en/default-lotus-config.toml
index 8d3c6a427e8..a26da4631bf 100644
--- a/documentation/en/default-lotus-config.toml
+++ b/documentation/en/default-lotus-config.toml
@@ -175,7 +175,7 @@
 [Chainstore]
   # type: bool
   # env var: LOTUS_CHAINSTORE_ENABLESPLITSTORE
-  EnableSplitstore = true
+  EnableSplitstore = false
 
   [Chainstore.Splitstore]
     # ColdStoreType specifies the type of the coldstore.
@@ -212,7 +212,7 @@
     #
     # type: uint64
     # env var: LOTUS_CHAINSTORE_SPLITSTORE_HOTSTOREFULLGCFREQUENCY
-    #HotStoreFullGCFrequency = 20
+    #HotStoreFullGCFrequency = 1
 
     # HotStoreMaxSpaceTarget sets a target max disk size for the hotstore. Splitstore GC
     # will run moving GC if disk utilization gets within a threshold (150 GB) of the target.
diff --git a/node/config/def.go b/node/config/def.go
index 1972b76371f..2281cc7fe0f 100644
--- a/node/config/def.go
+++ b/node/config/def.go
@@ -94,13 +94,13 @@ func DefaultFullNode() *FullNode {
 			SimultaneousTransfersForRetrieval: DefaultSimultaneousTransfers,
 		},
 		Chainstore: Chainstore{
-			EnableSplitstore: true,
+			EnableSplitstore: false,
 			Splitstore: Splitstore{
 				ColdStoreType: "discard",
 				HotStoreType:  "badger",
 				MarkSetType:   "badger",
 
-				HotStoreFullGCFrequency:      20,
+				HotStoreFullGCFrequency:      1,
 				HotStoreMaxSpaceTarget:       650_000_000_000,
 				HotStoreMaxSpaceThreshold:    150_000_000_000,
 				HotstoreMaxSpaceSafetyBuffer: 50_000_000_000,
diff --git a/node/modules/core.go b/node/modules/core.go
index a0d52c291bc..0d232acb1b2 100644
--- a/node/modules/core.go
+++ b/node/modules/core.go
@@ -70,7 +70,7 @@ func MemoryConstraints() system.MemoryConstraints {
 // MemoryWatchdog starts the memory watchdog, applying the computed resource
 // constraints.
 func MemoryWatchdog(lr repo.LockedRepo, lc fx.Lifecycle, constraints system.MemoryConstraints) {
-	if os.Getenv(EnvWatchdogDisabled) == "1" {
+	if val, isSet := os.LookupEnv(EnvWatchdogDisabled); !isSet || val != "0" {
 		log.Infof("memory watchdog is disabled via %s", EnvWatchdogDisabled)
 		return
 	}