Mounting GPT partitioned exFAT formatted disk on Ubuntu 20.04.6

Roon Software Discussion Linux
1

I wasn’t able to find the solution online, so maybe hope to find a guru here.

I am experimenting a new Roon server built on Ubuntu 20.04.6 (barebone, no GUI). Everything works fine, except that my music library stored in an exFAT formatted (per ROCK recommendation) USB 5TB disk cannot be mounted. The exFAT formatting was done on Mac OS. Apparently the disk is “GPT partitioned” so Ubuntu gives an additional error message and cannot read the “superblock”.

Does anyone know how to mount such a USB hard disk on Ubuntu 20.04.6? I’ve already installed exfat-utils, and the last step seems to be related to “gdisk” function instead of “fdisk”, but I am lost there about various options. First, I don’t know which option to choose to fix the partition block, and second, I wonder if this overwrites something to partition block so that the disk becomes no longer readable on Mac (which is clearly not what I want). Thank you.

1 Like
2

When you format the drive on macOS, there is a pop up menu for partition scheme, and the default is “GUID Partition Map”; you should instead try “Master Boot Record” and see if that changes things.

3

Thank you. The disk had been formatted already and has 2+ TB of music in it. I could wipe out and reformat, but I would like to avoid the hassle if possible.

So my specific question is: I see that gdisk allows me to write the partition table on the partition block on Ubuntu. Will this make the disk unreadable on Mac, or will it be readable on both Ubuntu and Mac?

4

There are a number of partition manager applications for Windows that will convert GPT partitioned disks to MBR partitioning.

However, for Mac’s, I am not so sure.

In any event, this is an high risk operation and so you should back up any data on the disk anyway and if you have back up of the data, then the time saved by converting the existing partition scheme rather than just wiping it and re-partitioning and formatting the drive will not be that signicant.

1 Like
5

Of course I’m not careless, and I have three identical copies of HD containing the library. I guess I can take a risk to destroy one of them, but would like to know what to expect. Thank you.

6

Well, “sudo gdisk /dev/sdb” and “w” didn’t work. Still cannot mount it because it can’t read the “superblock.” Still looking for the solution…

7

You’ve to use ‘r’ and then ‘g’ to change from GPT to MBR.

8

‘r’ and ‘g’ and ‘w’ destroyed the GPT partition completely. Now MBR is MBR only and GPT is not present…

9

You should be able to mount a disk with a gpt partition table using fstab without issue, look at a fstab tutorial.

1 Like
10

@Grasshopper So my HDD is GPT partitioned (exFAT) on Mac OS. Could you help me what I should edit into fstab on Linux? Thank you.

11

I’d have to look it up in a tutorial, like I did when I created my NUC about a year ago, running Debian to mount shares automatically at boot and map to a dir.
Look at a fstab tutorial, it’ll be trial and error and a learning curve, but that’s Linux :wink:

12

For those who are interested, here is what I discovered through the experiment:

  • Formatting the disk on Ubuntu with exfat, the disk is readable/mountable on both Ubuntu and Mac.
  • Formatting the disk on Mac Disk Utility as GPT ExFAT (MBR not possible for 4TB disk), it is read on Ubuntu but it creates two partitions, e.g. /dev/sdb and /dev/sdb1. It is sdb1 that needs to be mounted on Ubuntu.
2 Likes