@Danp
yes it's the same on XOA in trial mode latest patched.

@olivierlambert

I did not have a XOA i have the xo-server 5.54.0 community edition on ubunto server.

@badrAZ

lvscan
  ACTIVE            '/dev/ubuntu-vg/ubuntu-lv' [4,00 GiB] inherit
  ACTIVE            '/dev/mysqldata/mysqldata' [<120,00 GiB] inherit

pvscan
  PV /dev/xvda3   VG ubuntu-vg       lvm2 [<19,00 GiB / <15,00 GiB free]
  PV /dev/loop2   VG mysqldata       lvm2 [<120,00 GiB / 0    free]
  Total: 2 [138,99 GiB] / in use: 2 [138,99 GiB] / in no VG: 0 [0   ]

fdisk -l
Disk /dev/loop0: 89,1 MiB, 93417472 bytes, 182456 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop1: 88,5 MiB, 92778496 bytes, 181208 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/loop2: 120 GiB, 128849018880 bytes, 251658240 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/xvda: 20 GiB, 21474836480 bytes, 41943040 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 4EBCD4D4-BC5A-4F08-971C-AFB438AC5912

Device       Start      End  Sectors Size Type
/dev/xvda1    2048     4095     2048   1M BIOS boot
/dev/xvda2    4096  2101247  2097152   1G Linux filesystem
/dev/xvda3 2101248 41940991 39839744  19G Linux filesystem

Disk /dev/mapper/ubuntu--vg-ubuntu--lv: 4 GiB, 4294967296 bytes, 8388608 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/mapper/mysqldata-mysqldata: 120 GiB, 128844824576 bytes, 251650048 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

sudo lsblk --output NAME,FSTYPE,LABEL,UUID,MODE
NAME                      FSTYPE      LABEL UUID                                   MODE
loop0                     squashfs                                                 brw-rw----
loop1                     squashfs                                                 brw-rw----
loop2                     LVM2_member       lBivVu-YQOo-du2R-8DvU-3Igy-Kbk6-7MLtZU brw-rw----
└─mysqldata-mysqldata     xfs               c0875768-6bc8-49e5-85e9-fed64b469344   brw-rw----
sr0                                                                                brw-rw----
xvda                                                                               brw-rw----
├─xvda1                                                                            brw-rw----
├─xvda2                   ext4              e79dd49b-ed47-41b0-9b8a-720875dbdaf0   brw-rw----
└─xvda3                   LVM2_member       qNEetu-q1qF-AO2t-Eufa-OuoK-9Cy4-hjAstI brw-rw----
  └─ubuntu--vg-ubuntu--lv ext4              c1b5b0fa-42d1-494a-b2d0-4125c579a660   brw-rw----

Hi
Also not working on XO Server

$ df -Th
Filesystem                          Type      Size  Used Avail Use% Mounted on
udev                                devtmpfs  3,9G     0  3,9G   0% /dev
tmpfs                               tmpfs     795M 1020K  794M   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv   ext4      3,9G  3,6G   74M  99% /
tmpfs                               tmpfs     3,9G     0  3,9G   0% /dev/shm
tmpfs                               tmpfs     5,0M     0  5,0M   0% /run/lock
tmpfs                               tmpfs     3,9G     0  3,9G   0% /sys/fs/cgroup
/dev/loop0                          squashfs   90M   90M     0 100% /snap/core/8268
/dev/loop1                          squashfs   89M   89M     0 100% /snap/core/7270
/dev/xvda2                          ext4      976M   77M  832M   9% /boot
tmpfs                               tmpfs     795M     0  795M   0% /run/user/1000


  PV         VG        Fmt  Attr PSize    PFree
  /dev/loop2 mysqldata lvm2 a--  <120,00g      0
  /dev/xvda3 ubuntu-vg lvm2 a--   <19,00g <15,00g


  VG        #PV #LV #SN Attr   VSize    VFree
  mysqldata   1   1   0 wz--n- <120,00g      0
  ubuntu-vg   1   1   0 wz--n-  <19,00g <15,00g

  LV        VG        Attr       LSize    Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  mysqldata mysqldata -wi-a----- <120,00g
  ubuntu-lv ubuntu-vg -wi-ao----    4,00g

Here is no XFS

Hi

I have the same issue.
Log:

backupNg.listFiles
{
  "remote": "b7f45be2-dcd5-4126-8c07-97cd98c0e08a",
  "disk": "xo-vm-backups/f7c45148-210c-1b0f-5de8-40e1f6384db9/vdis/e51ca8db-ddcc-4ec7-8621-98a9b7a94507/2840c32c-7c9e-4ee1-906a-214464b183b7/20200119T170746Z.vhd",
  "path": "/"
}
{
  "command": "mount --options=loop,ro --source=/tmp/tmp-11237QOS1hgR2FZB/vhdi2 --target=/tmp/tmp-11236LS1KLJD2Iem",
  "exitCode": 32,
  "stdout": "",
  "stderr": "mount: /tmp/tmp-11236LS1KLJD2Iem: unknown filesystem type 'LVM2_member'.",
  "failed": true,
  "timedOut": false,
  "isCanceled": false,
  "killed": false,
  "message": "Command failed with exit code 32: mount --options=loop,ro --source=/tmp/tmp-11237QOS1hgR2FZB/vhdi2 --target=/tmp/tmp-11236LS1KLJD2Iem",
  "name": "Error",
  "stack": "Error: Command failed with exit code 32: mount --options=loop,ro --source=/tmp/tmp-11237QOS1hgR2FZB/vhdi2 --target=/tmp/tmp-11236LS1KLJD2Iem
    at makeError (/opt/xen-orchestra/node_modules/execa/lib/error.js:56:11)
    at handlePromise (/opt/xen-orchestra/node_modules/execa/index.js:114:26)
    at <anonymous>"
} 

Also 2 Disks . Disk 1 list ok , Disk 2 did not work
Server is a Cent OS 7
LVM:

[]# pvs
  PV         VG        Fmt  Attr PSize    PFree
  /dev/xvda2 centos    lvm2 a--   <29,00g    0
  /dev/xvdb  mysqldata lvm2 a--  <120,00g    0
[]# vgs
  VG        #PV #LV #SN Attr   VSize    VFree
  centos      1   2   0 wz--n-  <29,00g    0
  mysqldata   1   1   0 wz--n- <120,00g    0
[]# lvs
  LV        VG        Attr       LSize    Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root      centos    -wi-ao----  <26,00g
  swap      centos    -wi-ao----    3,00g
  mysqldata mysqldata -wi-ao---- <120,00g

Device file /dev/mysqldata/mysqldata
Current status Mounted on /mysqldata as xfs
Hope it helps.