# Make a disk bigger

> Grow an iSCSI disk on your server and use the new space on the Mac with BeamDisk's Use the New Space, including the one Terminal command macOS requires, and what happens if a disk gets smaller.

You can make a disk bigger on your server while it's in use. BeamDisk notices the new size and, with **Use the New Space**, grows the disk's APFS volume to fill it. Your files stay as they are.

## Grow a disk

1. On your server, make the disk bigger: on TrueNAS, edit the zvol and raise its size. Keep it a whole number of MiB or GiB.
2. In BeamDisk, open the disk's page. Once the server reports the change, it says **Grew on the server**, with the old and new sizes.
3. Quit the apps using the disk, then click **Use the New Space…** and confirm with **Use the New Space**.
4. BeamDisk ejects the disk for a moment, connects it again at its new size, extends its partition table if it has one, and attaches it again. The sidebar's message line follows each step.
5. The last step, growing the volume into the new space, is one macOS lets only Terminal or Disk Utility do, not an App Store app, so BeamDisk shows the command. Click **Copy Command**, paste it into Terminal and press Return.

The command is macOS's own, of the form `diskutil apfs resizeContainer disk13 0`, with your disk's number in it. It takes a moment and needs no administrator password.

## If you clicked Later

The disk's page reminds you while space is unused: **12 GB of this disk isn't used yet: its volume is smaller than the disk. Use the New Space grows it.** Clicking **Use the New Space…** again goes straight to the command, without ejecting the disk.

## Disks that aren't APFS

For a disk with no APFS volume (Mac OS Extended, for example), BeamDisk connects it at the new size and says **It has no APFS container to grow; Disk Utility can resize its volume.** Resize it in Disk Utility.

## Don't make a disk smaller

A disk made smaller on the server loses whatever was past its new end. BeamDisk says so: **Smaller on the server now**, with the old and new sizes, and **Check the server before using it: what was past the new end isn't there any more.**

## Related

- [Set up TrueNAS](https://beamdisk.app/docs/targets/truenas/)
- [A disk's page](https://beamdisk.app/docs/using/disk-page/)