diff --git a/pkg/cmd/roachtest/spec/cluster_spec.go b/pkg/cmd/roachtest/spec/cluster_spec.go
index 601856f928f2..57cdda164108 100644
--- a/pkg/cmd/roachtest/spec/cluster_spec.go
+++ b/pkg/cmd/roachtest/spec/cluster_spec.go
@@ -104,11 +104,16 @@ func awsMachineSupportsSSD(machineType string) bool {
 	return false
 }
 
-func getAWSOpts(machineType string, zones []string, volumeSize int, localSSD bool) vm.ProviderOpts {
+func getAWSOpts(
+	machineType string, zones []string, volumeSize int, localSSD bool, RAID0 bool,
+) vm.ProviderOpts {
 	opts := aws.DefaultProviderOpts()
 	if volumeSize != 0 {
 		opts.DefaultEBSVolume.Disk.VolumeSize = volumeSize
 	}
+	if RAID0 {
+		opts.UseMultipleDisks = false // NB: the default is true
+	}
 	if localSSD {
 		opts.SSDMachineType = machineType
 	} else {
@@ -137,12 +142,8 @@ func getGCEOpts(
 		opts.Zones = zones
 	}
 	opts.SSDCount = localSSDCount
-	if localSSD && localSSDCount > 0 {
-		// NB: As the default behavior for _roachprod_ (at least in AWS/GCP) is
-		// to mount multiple disks as a single store using a RAID 0 array, we
-		// must explicitly ask for multiple stores to be enabled, _unless_ the
-		// test has explicitly asked for RAID0.
-		opts.UseMultipleDisks = !RAID0
+	if RAID0 {
+		opts.UseMultipleDisks = false // NB: the default is true, i.e. no RAID0
 	}
 	opts.TerminateOnMigration = terminateOnMigration
 
@@ -250,7 +251,7 @@ func (s *ClusterSpec) RoachprodOpts(
 	var providerOpts vm.ProviderOpts
 	switch s.Cloud {
 	case AWS:
-		providerOpts = getAWSOpts(machineType, zones, s.VolumeSize, createVMOpts.SSDOpts.UseLocalSSD)
+		providerOpts = getAWSOpts(machineType, zones, s.VolumeSize, createVMOpts.SSDOpts.UseLocalSSD, s.RAID0)
 	case GCE:
 		providerOpts = getGCEOpts(machineType, zones, s.VolumeSize, ssdCount,
 			createVMOpts.SSDOpts.UseLocalSSD, s.RAID0, s.TerminateOnMigration)
diff --git a/pkg/cmd/roachtest/spec/machine_type.go b/pkg/cmd/roachtest/spec/machine_type.go
index af77a4e62e64..286dc6e01704 100644
--- a/pkg/cmd/roachtest/spec/machine_type.go
+++ b/pkg/cmd/roachtest/spec/machine_type.go
@@ -42,6 +42,9 @@ func AWSMachineType(cpus int, highmem bool) string {
 	}
 
 	// There is no c5d.24xlarge.
+	//
+	// TODO(tbg): there seems to be, see:
+	// https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/compute-optimized-instances.html
 	if family == "c5d" && size == "24xlarge" {
 		family = "m5d"
 	}
diff --git a/pkg/roachprod/vm/aws/aws.go b/pkg/roachprod/vm/aws/aws.go
index 2d36c4e04b2e..b18b771dd40f 100644
--- a/pkg/roachprod/vm/aws/aws.go
+++ b/pkg/roachprod/vm/aws/aws.go
@@ -203,6 +203,7 @@ func DefaultProviderOpts() *ProviderOpts {
 		RemoteUserName:   "ubuntu",
 		DefaultEBSVolume: defaultEBSVolumeValue,
 		CreateRateLimit:  2,
+		UseMultipleDisks: true, // don't default to RAID0
 	}
 }
 
diff --git a/pkg/roachprod/vm/gce/gcloud.go b/pkg/roachprod/vm/gce/gcloud.go
index 7dd364637f11..7b1efdeb2dbb 100644
--- a/pkg/roachprod/vm/gce/gcloud.go
+++ b/pkg/roachprod/vm/gce/gcloud.go
@@ -230,6 +230,7 @@ func DefaultProviderOpts() *ProviderOpts {
 		PDVolumeType:         "pd-ssd",
 		PDVolumeSize:         500,
 		TerminateOnMigration: false,
+		UseMultipleDisks:     true, // don't default to RAID0
 		useSharedUser:        true,
 		preemptible:          false,
 	}