[PVE-User] DeviceMapper devices get filtered by Proxmox

[Uwe Sauter]

Hi Alwin,

Am 25.07.23 um 12:40 schrieb Alwin Antreich:
> Hi Uwe,
> 
> July 25, 2023 9:24 AM, "Uwe Sauter" <uwe.sauter.de at gmail.com> wrote:
> 
>> So, I've been looking further into this and indeed, there seem to be very strict filters regarding
>> the block device names that Proxmox allows to be used.
>>
>> /usr/share/perl5/PVE/Diskmanage.pm
>>
>> 512 # whitelisting following devices
>> 513 # - hdX ide block device
>> 514 # - sdX scsi/sata block device
>> 515 # - vdX virtIO block device
>> 516 # - xvdX: xen virtual block device
>> 517 # - nvmeXnY: nvme devices
>> 518 # - cciss!cXnY cciss devices
>> 519 print Dumper($dev);
>> 520 return if $dev !~ m/^(h|s|x?v)d[a-z]+$/ &&
>> 521 $dev !~ m/^nvme\d+n\d+$/ &&
>> 522 $dev !~ m/^cciss\!c\d+d\d+$/;
>>
>> I don't understand all the consequences of allowing ALL ^dm-\d+$ devices but with proper filtering
>> it should be possible to allow multipath devices (and given that there might be udev rules that
>> create additinal symlinks below /dev, each device's name should be resolved to its canonical name
>> before checking).
> It is also a matter of ceph support [0]. Aside the extra complexity, using the amount of HDDs is not a good use-case for virtualization. And HDDs definitely need the DB/WAL on a separate device (60x disks -> 5x NVMe).

Well, if the documentation is to be trusted, there is multipath support since Octupus.
My use-case is not hyper-converged virtualization; I simply am using Proxmox due to its good UI and
integration of Ceph (and because it does not rely on containers to deploy Ceph).

I am aware that HDDs will need some amount of flash but I do have a couple of SAS-SSDs at hand that
I can put into the JBODs. And currently all this is just a proof of concept.

> Best to set it up with ceph-volume directly. See the forum post [1] for the experience of other users.

Thanks for the link though I have to support the arguments of the forum members that multipath is an
enterprise feature that should be supported by an enterprise-class virtualization solution.


Best,

	Uwe

> Cheers,
> Alwin
> 
> [0] https://docs.ceph.com/en/latest/ceph-volume/lvm/prepare/#multipath-support
> [1] https://forum.proxmox.com/threads/ceph-with-multipath.70813/