diff --git a/modules/logging/filewriter.go b/modules/logging/filewriter.go
index 0445ef06f..2e19ec843 100644
--- a/modules/logging/filewriter.go
+++ b/modules/logging/filewriter.go
@@ -108,7 +108,7 @@ type FileWriter struct {
 	RollSizeMB int `json:"roll_size_mb,omitempty"`
 
 	// Roll log file after some time
-	RollInterval time.Duration `json:"roll_interval,omitempty"`
+	RollInterval caddy.Duration `json:"roll_interval,omitempty"`
 
 	// Roll log file at fix minutes
 	// For example []int{0, 30} will roll file at xx:00 and xx:30 each hour
@@ -287,7 +287,7 @@ func (fw FileWriter) OpenWriter() (io.WriteCloser, error) {
 		MaxBackups:       fw.RollKeep,
 		LocalTime:        fw.RollLocalTime,
 		Compression:      compression,
-		RotationInterval: fw.RollInterval,
+		RotationInterval: time.Duration(fw.RollInterval),
 		RotateAtMinutes:  fw.RollAtMinutes,
 		RotateAt:         fw.RollAt,
 		BackupTimeFormat: fw.BackupTimeFormat,
@@ -489,11 +489,11 @@ func (fw *FileWriter) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 			if !d.AllArgs(&durationStr) {
 				return d.ArgErr()
 			}
-			duration, err := time.ParseDuration(durationStr)
+			duration, err := caddy.ParseDuration(durationStr)
 			if err != nil {
 				return d.Errf("parsing roll_interval duration: %v", err)
 			}
-			fw.RollInterval = duration
+			fw.RollInterval = caddy.Duration(duration)
 
 		case "roll_minutes":
 			// Accept either a single comma-separated argument or
diff --git a/modules/logging/filewriter_test.go b/modules/logging/filewriter_test.go
index de46891fa..2425381f3 100644
--- a/modules/logging/filewriter_test.go
+++ b/modules/logging/filewriter_test.go
@@ -23,6 +23,7 @@ import (
 	"path/filepath"
 	"syscall"
 	"testing"
+	"time"
 
 	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
 )
@@ -648,3 +649,69 @@ file /var/log/app.log {
 		t.Fatal("expected error for invalid dir_mode")
 	}
 }
+
+func TestCaddyfile_RollInterval(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		wantSecs float64
+		wantErr  bool
+	}{
+		{
+			name: "day unit",
+			input: `file /var/log/app.log {
+    roll_interval 1d
+}`,
+			wantSecs: 86400,
+		},
+		{
+			name: "hours unit",
+			input: `file /var/log/app.log {
+    roll_interval 24h
+}`,
+			wantSecs: 86400,
+		},
+		{
+			name: "minutes unit",
+			input: `file /var/log/app.log {
+    roll_interval 30m
+}`,
+			wantSecs: 1800,
+		},
+		{
+			name: "fractional days",
+			input: `file /var/log/app.log {
+    roll_interval 1.5d
+}`,
+			wantSecs: 129600,
+		},
+		{
+			name: "invalid duration",
+			input: `file /var/log/app.log {
+    roll_interval bogus
+}`,
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			d := caddyfile.NewTestDispenser(tt.input)
+			var fw FileWriter
+			err := fw.UnmarshalCaddyfile(d)
+			if tt.wantErr {
+				if err == nil {
+					t.Fatal("expected error but got none")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			gotSecs := time.Duration(fw.RollInterval).Seconds()
+			if gotSecs != tt.wantSecs {
+				t.Errorf("got %v seconds, want %v", gotSecs, tt.wantSecs)
+			}
+		})
+	}
+}