How to properly disable (temporarerly) a datastore?

[epionier]

Hello,
I have setup in a PBS an external USB-SSD-Disk as a datastore (name zfsbackupext) for offsite backups that are done once a week.
During the other days I want to disable the Datastore for the PBS because the USB disk is not connected to the PBS and reenable it when the USB disk is connected again.

I made a crontab with following commands:

/sbin/proxmox-backup-manager datastore update zfsbackupext --maintenance-mode=offline ->"disable before disconnection"
/sbin/proxmox-backup-manager datastore update zfsbackupext --delete maintenance-mode ->"enable after connection"

which works in terms of putting the datastore in maintenance mode and ending maintenance mode.

But now I receive every minute a log entry when the disk is not connected:

proxmox-backup-proxy[1762]: lookup_datastore failed - unable to open chunk store at "/mnt/datastore/zfsbackupext/.chunks" - No such file or directory (os error 2)

The USB disk was properly disabled/unmounted via crontab in following order:

/sbin/pvesm set PBS-localUSB -disable 1 -> disable PBS datastore storage in PVE
/sbin/proxmox-backup-manager datastore update zfsbackupext --maintenance-mode=offline -> put PBS datastore in maintenance mode
/sbin/zpool export zfsbackupext -> remove zfs file system (temporarerely)
root /usr/bin/echo 1 > /sys/block/sdc/device/delete 2>&1 -> disconnect USB disk / block device

Is there another way or even a better way to disable the USB datastore to prevent logging?

 

[groque]

Removable datastores are officially supported since Proxmox Backup Server 3.3. Instead of manually toggling maintenance mode or suppressing logs, you can define the datastore as removable and let PBS handle it. Full documentation: PBS Backup Storage - Removable Datastores

 

[epionier]

@groque
Thank you for your input. Removable Datastores only work with EXT4 oder XFS disks, not ZFS formatted disks like mine.

I have PBS and PVE installed on the same host (direct installation) and tried it with "removable datastore" and EXT4 directory in advance.
Unfortunately I was not able to get it working. When I tried to add a datastore with removable option I received unspecified errors.

I now tried it again with XFS directory as a removeable storage. This works but now I receive every minute the following when the removable USB is properly unmounted and block deleted in advance:

proxmox-backup-proxy[1762]: lookup_datastore failed - datastore 'XFS-USB-SSD' is not mounted

 

[_gabriel]

if PBS datastore is attached to PVE,
you need to disable PVE side too.
/sbin/pvesm set PBS-DatastoreName --disable 1

 

[epionier]

Hello _gabriel,
as you can see in my first example with the ZFS I disabled PVE PBS Storage at first.
In the second try with XFS PVE was not involved. The message comes from PBS and not PVE.

As far as I can see the logging that occurs with removable datastores as well is a known "bug":

J

Thread 'PBS und entfernbare Datastores'

Dec 9, 2024

Endlich kam ich mal dazu, die neue Funktion der entfernbaren Datastores zu testen, aber so ganz funktioniert das nicht so wie erwartet.
Beim Hinzufügen das Datastores kann man ja auswählen, dass man den bereits existierenden Datastore wieder verwenden will (was schon mal sehr nice ist!) und dass es sich um einen entfernbaren Datastore handelt.

Wie man hier auch schön sehen kann, kann man das RDX Laufwerk mit /dev/sdb1 auswählen.
Allerdings speichert der PBS als backing-device die UUID der einzelnen RDX-HDD in der datastore.cfg ab und nicht /dev/sdb1!
Beim Wechsel der RDX...

• JensF
• Replies: 19
• Forum: Proxmox Backup Server (Deutsch/German)

• 

 

[_gabriel]

indeed, I was reading too fast.
Reproducible here.
For use case, where PBS Datastore is only USB, I only start PB-Proxy service during backup/sync/GC/verif then stop PB-Proxy service and unmount drive to allow hotplug.