Re: [Xen-users] Persistent block device naming by UUID

[Predrag Punosevac <punosevac72@xxxxxxxxx>]

Hans van Kranenburg <hans@xxxxxxxxxxx> wrote:

> Hi,
> 
> On 2/22/19 5:20 AM, Predrag Punosevac wrote:
> > [...]
> > 
> > I am reading documentation back and forth in search of a better
> > persistent naming method. Namely 
> > 
> > disk = [ 'phy:/dev/sdc,xvda,rw' ]
> > 
> > is not persistent between the boots. I like putting my DomUs on a
> > dedicated block devices (M.2 SSDs) and when one of them dies the disk 
> > labels are switching on the reboot. Ideally I would like to have
> > something like
> > 
> > disk = [ 'phy:UUID="839ca898-db1d-4c89-ad3f-faf6909bf448",xvda,rw' ]
> 
> What about...
> 
> disk = [
>     '/dev/disk/by-uuid/839ca898-db1d-4c89-ad3f-faf6909bf448,raw,xvda,rw'
> ]

Probably works on Debian. Red Hat also have /dev/disk/by-uuid

/dev/disk/by-uuid
[root@lake by-uuid]# ls
19cbce97-75fb-4350-bbf4-fc18206129f8
b67d3f41-ea4a-4581-b1c8-cfc02c573ef5
b2e35c42-6bca-44b9-b2dd-15ff62750de1
dd4e82e7-1042-4276-be28-59cc5b1a30ac

but on Alpine linux that directory doesn't exist

xen1:~# ls /dev/disk
ls: /dev/disk: No such file or directory

even though I can mount disks from fstab using UUID as follows

UUID=7e0dcf46-d8e1-405d-835d-8a9d76d2d394       /xen-images     xfs
defaults        0 0


I think this is now a question for Alpine Linux mailing list

> 
> By the way, the phy: format is long deprecated. See man 5
> xl-disk-configuration about that.
> 

Point well taken! I fixed my configuration files. The original syntax
was taken from Alpine Linux Wiki which is not updated very frequently. 


Thank you so much for you kind answer.

Best,
Predrag


> > instead. That seems to be unsupported
> 
> Well, you have the symlinks in /dev/ ;-]
> 
> > https://xenbits.xen.org/docs/4.11-testing/
> > 
> > I do understand that uuid in Xen lingo is used for something else
> > 
> > https://www.practicalxenserver.org/tutorials/miscellaneous-tutorials/working-with-uuids/
> > 
> > Am I missing here something?
> 
> Hans

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