RPi Move USB HDD?

[Baldchap]

I have a Raspberry Pi running PiHole, Unbound and Samba on my network and it works well.

After a recent overhaul it's running off a Pi5 with two USB HDDs. One is used for the OS and the Pi boots from this and logs to it etc (no SD cards in sight!), the other is simply a filestore with user folders for nightly phone backups.

I'd like to add another USB HDD and duplicate the first HDD to it. This part is easy and I'm not worried about it and yes I know a Synology NAS would be far better etc. etc.

My question is this: If I move the OS HDD into a different USB slot, is the OS clever enough to find it and boot from it, or does it rely on it being in the port where it was configured?

Thanks.

[WrekinCrew]

Why not try moving the existing boot drive to another slot and see if it boots?
I'm pretty sure it will; raspi-config doesn't ask which USB port to boot from.

[outnumbered]

Baldchap said:

I have a Raspberry Pi running PiHole, Unbound and Samba on my network and it works well.

After a recent overhaul it's running off a Pi5 with two USB HDDs. One is used for the OS and the Pi boots from this and logs to it etc (no SD cards in sight!), the other is simply a filestore with user folders for nightly phone backups.

I'd like to add another USB HDD and duplicate the first HDD to it. This part is easy and I'm not worried about it and yes I know a Synology NAS would be far better etc. etc.

My question is this: If I move the OS HDD into a different USB slot, is the OS clever enough to find it and boot from it, or does it rely on it being in the port where it was configured?

Thanks.

Have a look in /etc/fstab. If you see relevant lines that start with PARTUUID then it's safe to move the drive between USB ports (this has been the case for some years now).