iSCSI on a Mac with Apple Silicon

macOS doesn’t include an iSCSI initiator, the software that connects a computer to iSCSI storage. Windows and Linux do. To use an iSCSI target on a storage server or SAN, a Mac needs a third-party initiator.

The options on Apple Silicon

• A kernel-extension initiator. On a Mac with Apple Silicon, a kernel extension only loads after you restart into Recovery, lower the Mac’s security policy to Reduced Security, approve the extension in System Settings and restart again, on every Mac.
• A file share instead. SMB or NFS gives the Mac a shared folder rather than a disk. It’s not iSCSI, and the server keeps the file system.
• BeamDisk. A sandboxed Mac App Store app that connects to iSCSI targets with no kernel extension. The disk appears in Finder, Disk Utility and Time Machine like a local drive, and reads at over 1 GB/s on 10 GbE.

What you need

• A Mac with Apple Silicon on macOS 27 or later.
• An iSCSI target with at least one disk (LUN). BeamDisk is tested with TrueNAS and with Linux targets (LIO / targetcli).
• The target must allow your Mac’s initiator name, which BeamDisk shows in its window under This Mac.

Set up BeamDisk

1. Install BeamDisk from the Mac App Store, and turn it on in System Settings when it asks.
2. Allow your Mac on the target. Copy the initiator name from BeamDisk (This Mac, or Settings → General) and add it to the target’s allowed initiators on your server.
3. Add Disk. In BeamDisk, click Add Disk and enter your server’s address, and its CHAP user and secret if it uses CHAP.
4. Find Disks. Click Find Disks, tick the disks you want and name them.
5. Add them. Click Add 1 Disk (or Add 2 Disks, and so on). The first time, click Connect All, then Allow… when BeamDisk asks to attach disks. The disks appear in Finder; format an empty one as APFS with Format… on its page.

The full walkthrough has every option.

Frequently asked questions

Does macOS have a built-in iSCSI initiator?

No. Windows and Linux include one, but macOS doesn't, so a Mac needs third-party software to use an iSCSI target.

Can I use iSCSI on an M1, M2, M3 or M4 Mac?

Yes. BeamDisk runs on every Mac with Apple Silicon on macOS 27 or later, with no kernel extension.

Do I need to lower my Mac's security to use iSCSI?

Not with BeamDisk. Kernel-extension initiators need Reduced Security on Apple Silicon; BeamDisk is a sandboxed Mac App Store app and leaves the Mac's security settings as they are.

Is an iSCSI disk the same as a network share?

No. With SMB or NFS, the server manages the files and the Mac sees a shared folder. With iSCSI, the server provides a block device, the Mac formats it (APFS, for example), and it behaves like a disk plugged into the Mac. One Mac uses an iSCSI disk at a time.