[pbs-devel] [PATCH proxmox-backup v14 00/26] add removable datastores

[Dominik Csapak]

On 11/25/24 14:15, Lukas Wagner wrote:
> On  2024-11-22 15:46, Hannes Laimer wrote:
>> These patches add support for removable datastores. All removable
>> datastores have a backing-device(a UUID) associated with them. Removable
>> datastores work like normal ones, just that they can be unplugged. It is
>> possible to create a removable datastore, sync backups onto it, unplug
>> it and use it on a different PBS.
>>
>> The datastore path specified is relative to the root of the used device.
>> Removable datastores are bind mounted to /mnt/datastore/<NAME>.
>> Multiple datastores can be created on a single device, but only device with
>> a single datastore on them will be auto-mounted.
>>
>> When a removable datastore is deleted and 'destroy-data' is set, the
>> device has to be mounted. If 'destroy-data' is not set the datastore
>> can be deleted even if the device is not present. Removable datastores
>> are automatically mounted when plugged in.
>>
> 

[snip]

> 
> - Something that also was a bit confusing was the following:
>    - Attached new disk to my PBS test VM
>    - Formatted the disk as ext4 using the webui (name: disk1, device: sdb1), opting to NOT create a datastore as part of the formatting process
>    - Created a removable datastore on the new partition (name: disk1-store, device: sdb1)
>    -> This led to the partition being mounted twice:
> 
> /dev/sdb1 on /mnt/datastore/disk1 type ext4 (rw,relatime)
> /dev/sdb1 on /mnt/datastore/disk1-store type ext4 (rw,relatime)
> 
>    -> if 'unmount' is pressed for the datastore, only the second mount is unmounted. This could be confusing
>      to users who expect to be able to safely remove the disk after unmounting the datastore.
> 
>    - For contrast, if while creating the partition one opts to create the removable datastore immediately,
>      the partition is only mounted once.
> 
> 

i had slightly different, but also confusing experience

did basically the same as Lukas, but my target path was the exact same as the already mounted disk
which lead to an 'it's already mounted' error
(which yeah was expected, i just created the disk)

in that case we could e.g. try to simply use the already mounted path for that?
(idk how much work checking if it's the right on, etc. that would involve though...)