File systems
Each disk is inspected before it appears in Finder, and what’s on it decides how this Mac can use it.
| On the disk | In BeamDisk |
|---|---|
| APFS | Read and write |
| Mac OS Extended (Journaled) | Read and write |
| exFAT, FAT, Mac OS Extended (not journaled) | Read-only |
| NTFS | Read-only: macOS can only read NTFS |
| Nothing yet | Empty disk: format it |
| Linux, ZFS, VMware and other file systems macOS can’t read | Not attached: Unreadable here |
A disk that shows Unreadable here stays connected but is never attached, so it can’t be erased by mistake. Its Contents row says what BeamDisk found, where it can tell.
Some things are APFS-only: giving free space back to the server, and using new space after a disk grows. For a disk you’ll use only from Macs, use APFS: Format a new disk.
Sector size
Section titled “Sector size”Disks have 512-byte or 4,096-byte (4 KiB) sectors, set on the server. BeamDisk reads and writes both, with one exception:
- A disk written with 4 KiB sectors by Windows, Linux or another initiator opens read-only. Its state reads Read-only, with 4 KiB sectors beside it in the Overview, and Add Disk warns about it before you add it.
- A 4 KiB disk formatted on this Mac can then only be read with BeamDisk, not by Windows, Linux or other initiators. BeamDisk says so on the disk’s page. For a disk that may move between systems, use 512-byte sectors (on TrueNAS, keep the extent’s default): see Set up TrueNAS.
Disks with problems
Section titled “Disks with problems”If a disk’s partition table is damaged, overlaps or runs past the end of the disk, BeamDisk opens it read-only at most, and its page lists what it found when it connected, such as Its partition table is damaged; the backup copy is intact. A disk made smaller on the server is one way to get there: see Make a disk bigger.
On a disk with several partitions, any that macOS can only read are mounted read-only, and the others as usual.