[pve-devel] [PATCH installer] fix behavior if zfs disks have no by-id path

Aaron Lauterer a.lauterer at proxmox.com
Wed Feb 19 12:24:53 CET 2020

On 2/19/20 7:47 AM, Thomas Lamprecht wrote:
> On 2/18/20 5:55 PM, Aaron Lauterer wrote:
>> in some situations it is possible, that a disk does not have a
>> /dev/disk/by-id path, mainly AFAICT inside VMs with virtio disks.
> can this happen at all for real devices? And which "virtio" devices are you
> talking about, as "virtio-blk" isn't supported and "virtio-scsi" works here.
> The fallback looks always OK to do, but still some rationale would be
> good, for future decision making ;-)

Yeah, I wanted to be done with it last night and go home ;)

I can reproduce it with virtio-blk when installing it on PVE as well as 
VMware workstation pro.

We had at least two users reporting problems in the past days. One was 
trying to give PVE a test drive in VMware workstation pro and used the 
default paravirtualized SCSI it offers [0].

Another user wanted to test PVE on KVM [1] with virtio-block disks.

In these situations the disks do not show up in the /dev/disk/by-id path 
and the installer fails because it does not fall back to the /dev/sda, 
/dev/vda paths.

Even though it is not officially supported, it did work before the 
commit e1b490865f750e08f6c9c6b7e162e7def9dcc411 because this case was 
handled in the code block above:
foreach my $di (@$bootdevinfo) {
     my $devname = $di->{devname};
     $di->{by_id} = find_stable_path ("/dev/disk/by-id", $devname);

     my $osdev = find_stable_path ("/dev/disk/by-id", $di->{osdev}) || 

     $vdev =~ s/ $devname/ $osdev/;

If you want I can send a v2 with a more detailed description of the 
problem in the commit message.

[1] https://forum.proxmox.com/threads/installation-on-raidz-1-fails.65603/

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