PM 6.* ZFS pools with disk by id, why?

[mailinglists]

Hi guys,

is there any reason (except for race cases when /dev/sd* device names change) why since PM 6 installer switched from /dev/sdX to /dev/disks/by-id/* names when creating rpool?

I guess some documentation like one here:
https://pve.proxmox.com/wiki/ZFS:_Tips_and_Tricks
should be updated to use disk IDs?

Also HTTPS GUI still creates zfs pools using /dev/sd*, so I manually created additional pools, to have consistent naming of devices in my ZFS pools on the same server.

 

[guletz]

is there any reason (except for race cases when /dev/sd* device names change) why since PM 6 installer switched from /dev/sdX to /dev/disks/by-id/* names when creating rpool?

Yes. Think that for example one of your hdd is broken (let say sdb). Now you decide to stop your server, and to replace sdb with a new disk.
How do you find what phisical sdb is? With a pool with 2 disk is 50% chanse to be wrong. But with 8 hdd?

With by-id is very simple because this ID is the same ID that is print on the hdd label. So when I put any hdd in a server I make photos of the hdd label and the slot position in the server.

Good luck!

 

[guletz]

I guess some documentation like one here:
https://pve.proxmox.com/wiki/ZFS:_Tips_and_Tricks
should be updated to use disk IDs?

Yes if you do not want to go in big problems.

 

[mailinglists]

I guess we should open a feature request to fix this documentation as well as to make https GUI ZFS pool creation also reference devices by-id.
Anyone from proxmox team wants to do it?

 

[kappclark]

Wld like to follow up on this -- and I hope this makes sense ..

I have 2 i TB drives which I wld like to use as zfs mirror, and wld like to follow the advice of using disk-by-id and not the fleeting/changeable /dev/sdxx format.

The 2 disks appear in the /dev/disk/by-id directory, but they appear twice with different prefixes:

ata-st1000dm003 .....etc etc

wwn-0x500c500etc etc....


question is -- which of these id's shouls I use ?? is the second expression a mount point for the system ???

I am assuming the ata expression is what I want to use ...

Thank you for this ...

 

[guletz]

Hi,

Any form is ok (wwn or ata). Some dedicated storage have displays who can show wwn.. . For normal users ata is more useful I think because it have the SN of the hdd witch you can see it on the hdd label.

Good luck / Bafta