---
title: blockDeviceIdentifier
framework: virtualization
role: symbol
role_heading: Instance Property
path: virtualization/vzvirtioblockdeviceconfiguration/blockdeviceidentifier
---

# blockDeviceIdentifier

The string that identifies the VIRTIO block device.

## Declaration

```swift
var blockDeviceIdentifier: String { get set }
```

## Discussion

Discussion Use blockDeviceIdentifier to name devices so they’re more discoverable in the Linux guest. The identifier must be an ASCII encodable string of 20 bytes or less. Validate the identifier string using validateBlockDeviceIdentifier(_:) before attempting to set this property, for example: let idString = "ProjectData" do {     try VZVirtioBlockDeviceConfiguration.validateBlockDeviceIdentifier(idString)     blockDeviceIdentifier = idString } catch {     // Handle error as appropriate.     throw error } warning: Setting the identifier to an invalid string results in a fatal error that terminates the app. In a Linux guest, device identifiers are visible in the /dev/disk/by-id/ directory.