@olivierlambert
Hello,
I created a new SR and installed a new VM and
installed a new XO.
The last one was definitely the answer.
It's working now, so as far as backup via XO goes.
I tested everything extensively, with different VM, SR and different drive fill levels, all ok.
A manual snapshot won't work, but that's what it is.
My old XO installation, unfortunately I didn't write down the version, was from January. Also, when I reinstalled, I switched from stable to latest as you indicated.
Unfortunately, I can't say whether the pure stable update or the change to latest was the solution.
But the main thing is a happy ending.
Greetings Joerg

Hello, here my test of version 8.3 in the last weeks:

I tried to put everything I could think of in or on the machine. Different hardware and different versions of Windows and Linux, backup of XO, with and without Xen tools, etc.
So far no crashes or major problems, even if I drove the machine to the limits of its resilience, everything runs smoothly and for days, for this a thumbs up.

Hardware:
Dell Poweredge 730, CPU 2x E5-2698 V4, 512GB RAM
2 x Intel I350 1Gb adapters
2 x Intel X540-AT2 10Gb adapters
1 x Dell H730P mono Raid Controller (5 x 8TB Disk in Raid5)
2 x SSD in Raid 1 as Boot Drive
1 x PCie NVMe Adapter (4 x 2TB NVMe Disk in Softraid 5)
( Yummi, over 1 GByte/sec write speed in a VM with 2 TB of Data)
1x Nvidia K80 GPU card

This is without a doubt the biggest test machine I've ever had.

I have tested so far:
All standard functions (Copy, Move, Migrate, Snapshot etc.)
Use of GPU (Windows VM)
PCI passthrough (Windows, Linux - NetCard, USB, PCI card)
SR-IOV (see comments below)
Backup with XO
Heavy network load (copy 26TB of data via 10 GB netcard)
Heavy CPU and GPU load (8 VM with CPU at maximum for hours)
Fast copying of large data between the different SRs in the system.

With the exception of the SR-IOV, no problems were encountered and the performance was excellent in all respects.

What made me very happy was the installation of Xen-Tools under Windows 2022. I have often had the experience that after a Windows update the server no longer wanted to start due to a driver update. The problem seems to have disappeared completely, all drivers were installed automatically when the server was installed and have so far survived all updates from Microsoft without any problems. I only had to manually add the management agent.

SR IOV:
The two Intel I350 1Gb adapters no longer show up as SR-IOV adapters and have lost that functionality. They still worked under 8.2.
The Intel X540-AT2 adapters have the SR-IOV function. But when I use it, the adapter port shuts down after a short time. The Xen server still shows the card as connectet, but the network function is gone. The coupled switch shows the port as deactivated. In between, the network function is there again for a short time and the switch also shows this. The second 10 GB port runs error-free all the time. If I switch off the SR-IOV of the port, it works without any problems. Both as a normal Xen-Nic and in PCI passthrough. I copied TByte over the port, no errors.
It must be somehow due to the SR-IOV that apparently no longer works under 8.3.
I would be interested to know if others have experienced something similar or if everything works there.

I would like to test the "VM snapshot with disk exclusion" but somehow I can't do it. Both the snapshot and the XO always back up the entire VM with all disks. I'm sure it's error 50 (50cm in front of the keyboard) . Is there a detailed description of how to set it up somewhere?

Unfortunately I haven't been able to test any pool functions yet, so I have to set up a second machine for that. I can't get a second machine that size. I will probably have to build 2 smaller systems with shared storage and test them there.

If anyone thinks of anything else I could test, let me know

So far everything looks very good, you did a great job.

Greetings Joerg

@stormi
Hello, here the results on my server:

Test server:
Dell Poweredge R730
2 x Xenon E5-2698v4
512GB RAM

./xtf-runner selftest -q --host
Combined test results:
test-hvm32-selftest                      SUCCESS
test-hvm32pae-selftest                   SUCCESS
test-hvm32pse-selftest                   SUCCESS
test-hvm64-selftest                      SUCCESS
test-pv64-selftest                       SUCCESS

./xtf-runner -aqq --host
Combined test results:
test-hvm32-umip                          SKIP
test-hvm64-umip                          SKIP
test-pv64-xsa-167                        SKIP
test-pv64-xsa-182                        SKIP
Echo Result 3

/usr/libexec/xen/bin/test-cpu-policy
CPU Policy unit tests
Testing CPU vendor identification:
Testing CPUID serialise success:
Testing CPUID deserialise failure:
Testing CPUID out-of-range clearing:
Testing MSR serialise success:
Testing MSR deserialise failure:
Testing policy compatibility success:
Testing policy compatibility failure:
Done: all ok
Echo Result 0

@tjkreidl
Hello again,
thanks for your help, you put me on the right path.
I wrote to Olivier what I dit.
Greetings Jörg

@tjkreidl
Yes I believe that too

@olivierlambert
Hello,
I created a new SR and installed a new VM and
installed a new XO.
The last one was definitely the answer.
It's working now, so as far as backup via XO goes.
I tested everything extensively, with different VM, SR and different drive fill levels, all ok.
A manual snapshot won't work, but that's what it is.
My old XO installation, unfortunately I didn't write down the version, was from January. Also, when I reinstalled, I switched from stable to latest as you indicated.
Unfortunately, I can't say whether the pure stable update or the change to latest was the solution.
But the main thing is a happy ending.
Greetings Joerg

@olivierlambert
by the way: which version of XO are you using, not that I am using an older one and that the cause is there.
My drives are also local LVM so should be "Thick" too.

@olivierlambert
I will make a retry of the test.
Is the drive empty or filled with data
If the disk are empty it works for me to.

@olivierlambert
Seems like that to me too. Let me know if you found a solution. I leave the test VM on my Xen server so that I can test again at any time.

@olivierlambert
Exactly, it looks like the snapshot of the entire VM is always calculated first. If there is enough space then only the selected drive is taken in the backup, if not the Backup is aborted.
In other words, only if you can take a manual snapshot of the VM, XO's backup will then only backup the selected drive.
It would be good if the backup only checked whether there was enough space for a snapshot of the selected drive.

@olivierlambert
Here as promised a test of the [NOBAK] function.

About the SR:
NVME Raid
Size: 2.4 TB used of 5.5 TB total (2.9 TB allocated)

About "SRV-Test" VM:
0 "SRV-Test" "NVME Raid" 50GB /dev/xvda
1 "[NOBAK] SRV-Test Drive" "NVME Raid" 1.5 TB /dev/xvdb

Manual snapshot takes both drives and ignores the [NOBAK]
Backup via Xo works, only the first drive is backed up.
You can follow this under TASKS in the XO.
Under "File Restore" in the XO there are no data for the second drive.

So beautiful - so good. The idea would actually be to back up a server with very large drives partially.

So I change my VM to the following:
0 "SRV-Test" "NVME Raid" 50GB /dev/xvda
1 "[NOBAK] SRV-Test Drive" "NVME Raid" 1.5 TB /dev/xvdb
2 "[NOBAK] SRV-Test second test drive" NVME raid 2 TB /dev/xvdc

My SR looks know:
NVME Raid
4.4 TB used of 5.5 TB total (4.9 TB allocated)

Exactly the same result as the first test, both with the manual snapshot and with the XO backup.
Actually, the manual snapshot should not work at all, because there is not enough space on the SR to include all the drives, but due to thin provisioning it works because the drives are almost empty.

Now I'm filling the drives with data so I'm sure there isn't enough space on the SR for a full snapshot of all the data.

As expected, I get the error message "The specified storage repository has insufficient space" when taking a manual snapshot Everything is understandable since the manual snapshot saves the entire VM and there is no space for the 3.5 TB snapshot on the SR.

Now I make another backup with XO, which previously only backed up the 50 GB of the first drive.
UPS ... After a few seconds, the error "SR_BACKEND_FAILURE_44(, There is insufficient space, )" and the backup was aborted.

So, XO seems to first test whether a complete backup/snapshot can be created with all drives and then backs up the 50 GB of the first drive.
In my opinion a bit suboptimal because it doesn't solve the problem to always have twice the space on the SR as you used, even if I only want to back up the system disk of a VM with a few GB, for example.

Conclusion of the test:
A) Manual Snapshot with only part of drives ([NOBAK]), does not work.
B) Backup with XO with only part of the drives ([NOBAK]), works, but only if there is enough space for a complete snapshot of the VM on the SR.

Hope you can use with my little test for something.

@olivierlambert
I'm trying that this weekend.
Thanks in advance.

@olivierlambert

Great relief, I was beginning to have doubts about myself

@olivierlambert
Hmmm. Tried rename the Disk "SRV-File-Debian-10.10" in "[NOBAK] SRV-File-Debian-10.10"
It does not work!

@olivierlambert said in XCP-ng 8.3 public alpha :

snap disk exclusion

Thank you too.
I use the SR-IOV under 8.2 and it work there on the same netcard. I don't think these are suddenly broken.

A description for the snap disk exclusion would be great, I hate error 50