and you shouldn’t be using any of those, since the order can and will change. The numbers are based on the order the devices and device drivers are initialized in, not based on physical location in the system. The modern approach (assuming you’re using udev) is to use the symlinks in /dev/disk/by-id/ or /dev/disk/by-uuid/ instead, since both are consistent across reboots (and by-id should be consistent across reinstalls, assuming the same partitioning scheme on the same physical drives)
This is also why Ethernet devices now have names like enp0s3 - the numbers are based on physical location on the bus. The old eth0, eth1, etc. could swap positions between Linux upgrades (or even between reboots) since they were also just the order the drivers were initialized in.
I’m sure you know this, but to to supplement your comment for future readers, UUIDs are also a good solution for partitions.
I think OP’s point was that UUIDs can still change, but the stuff that makes up the /by-id/ names cannot. Granted, those aren’t applicable to partitions.
Are UUIDs built into the hardware, or something your computer decides on based on the drive’s serial number and shit?
According to Arch Wiki they get generated and stored in the partition when it is formatted. So kinda like labels but automated and with (virtually) no collision risk.
No. Since each partition gets its own UUID, it means it’s generated by the OS on creation, no matter the number of partitions. On boot kernel will scan all UUIDs and then mount and map according to them, which is sightly less efficient method than naming block device directly, but far easier for humans and allows you to throw your drives to whichever port you like.
So if we swap drives about, the OS will see them as the same drive and/or partition?
Back in my day, /dev/hda was the primary master, hdb was the primary slave, hdc was the secondary master and hdd was the secondary slave.
Nothing ever changed between reboots. Primary/secondary depended on which port the ribbon cable connected to on the motherboard, and primary/secondary master/slave was configured by a jumper on the drive itself.
I have a hatred for the enp id thing as it isn’t any better for me. It changes on me every time I add/remove a hard drive or enable/disable the WiFi card in the BIOS. For someone who is building up a server and making changes to it, this becomes a real pain. What happens if a drive dies? Do I have to change the network config yet again over this?
How is that happening? The number on the bus shouldn’t change from adding or removing drives. I could imagine this with disabling a card in UEFI / BIOS if that basically stops reporting the bus entry completely. But drives?
Anyhow, if I’m not mistaken, you can assign a fixed name based on the reported MAC.
It is only the nvme drives that do it. That damn PCI busses and iommu groups get renumbered every damn time I remove or add one. The SATA is safe though.
Use a systems rule to give it a consistent name based on its MAC address, driver, etc. I just had this exact same problem setting up my servers.
root@prox1:~# cat /etc/systemd/network/10-persistent-10g.link
[Match]
Driver=atlantic
[Link]
Name=nic10g
root@prox1:~# cat /etc/systemd/network/10-persistent-1g.link
[Match]
Driver=igb
[Link]
Name=nic1g
