[nc-format-usb] partition alignment

Hi everyone,

I am using NextcloudPi on an ODroid HC2 with a SATA attached 4TB WDRed hard drive. The drive was formatted with nc-format-usb as one BTRFS volume, no trouble so far.

But a $ sudo fdisk -l shows the following output:

Disk /dev/sdb: 3.7 TiB, 4000787030016 bytes, 7814037168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 33553920 bytes
Disklabel type: gpt
Disk identifier: removed by author

Device Start End Sectors Size Type
/dev/sdb1 65535 7814000189 7813934655 3.7T Linux filesystem

Partition 1 does not start on physical sector boundary.

This seems to be no crtical issue, but a performance reduction is observed by other users (not necessarily on NextcloudPi).

Are there any means to avoid the misalignement while using nc-format-usb?

Also I am using an additional HDD plugged in via USB for backup purposes. As a feature request it would be helpful to differentiate the disks in nc-format-usb.

Thanks for feedback, this project is really great.
I wish you all the best for 2019.

Kind regards

funkmastergst

Start at the nc-format-usb entry point and inspect how it creates the GPT partition shown by fdisk. Reproduce the report with a 4K-sector disk and verify the resulting start sector is aligned; the issue also requests a way to distinguish disks when selecting the formatting target.