# Time Machine over iSCSI

> Back up a Mac with Time Machine to an iSCSI disk on your server with BeamDisk: connect an empty disk, install BeamDisk's Time Machine profile once, and choose the disk in Time Machine.

With BeamDisk, a disk on your server can be a Time Machine destination, just like a drive plugged into the Mac.

## What you need

- BeamDisk on a Mac with Apple Silicon, macOS 27 or later.
- An empty disk on your server for this Mac, connected with BeamDisk ([Add your first disk](https://beamdisk.app/docs/getting-started/add-a-disk/)). Give it room: Time Machine keeps many versions.
- An administrator's password, to install the profile and to change Time Machine's settings.

## Set it up

1. **Connect an empty disk** with BeamDisk, and format it as APFS with Format… if it's new.
2. **Install the profile.** In BeamDisk's Settings → Time Machine, click Install Profile…, and System Settings opens at Device Management: under Downloaded, double-click "BeamDisk: Time Machine support", click Install…, then Install, and enter an administrator's password.
3. **Choose the disk.** Click Open Time Machine Settings, click +, and choose the disk.

Time Machine may create its own backup volume on the disk, named after the disk with a number, such as "Backups 1". Backups then run on Time Machine's usual schedule.

The [Time Machine guide](https://beamdisk.app/docs/time-machine/set-up/) covers restoring and what to expect.

## Frequently asked questions

### Can Time Machine back up to an iSCSI disk?

Yes, with BeamDisk. After a one-time setup in BeamDisk's settings, the iSCSI disk can be chosen as a Time Machine destination like a disk plugged into the Mac.

### How fast is a Time Machine backup over iSCSI?

In BeamDisk's tests on 10 GbE to a TrueNAS SSD pool, the first full backup of a Mac (71.4 GB, 1.8 million files) took 8 minutes 19 seconds, against 9 minutes 39 seconds for the same backup over SMB to the same pool. Later backups copy only what changed; one with 5.8 GB of new files took about a minute either way.

### Why does Time Machine ask for an administrator password?

While BeamDisk's Time Machine profile is installed, Time Machine settings ask for an administrator's password before changes.

### Can several Macs back up to one iSCSI disk?

No. BeamDisk gives each disk to one Mac at a time, so give every Mac its own disk on the server.