@MathieuRA said: Hi, regarding your backups which do not appear on the XO5 restore page, I suggest you to open a new topic Forgot to include the link to the new topic https://xcp-ng.org/forum/topic/12040/restore-only-showing-1-vm

@Pilow said: @ph7 try to put RETENTION to 1 in the schedule, as you are using LTR parameters I was running the shedule with 20 mins backup retention and it is running fine together with the LTR And here is the manual I ran at 14:56 removed [image: 1775140196713-screenshot-2026-04-02-at-16-28-13-backup.png]

@Pilow perfect!

This issue appears to have been resolved by a recent change.

@Pilow open a dedicated topic on this . I will ping the relevant team there is it iscsi + CBT ?

@JSylvia007 Sorry, I'm really late to this thread, but note that backups can become problematic if the SR is something like 90% or more full. There needs to be some buffer for storage as part of the process. The fact you could copy/clone VMs means your SR is working OK, but backups are a different situation. If need be, you can always migrate VMs to other storage which is evidently what you ended up doing, which frees up extra disk space. Also backups are pretty intensive so make sure you have both enough CPU capacity and memory to handle the load. Finally. a defective SR will definitely cause issues if there are I/O errors, so watch your /var/log/SMlog for any such entries.

And this is the result [image: 1774531386302-screenshot-2026-03-21-at-09-31-45-backup.png]

@florent I rebuilt my XCP hosting environment (everything is faster and bigger stuffed into one rack).... and this issue is now worse. The main changes to this new setup are 2x40Gb networking, faster NFS NVMe NAS, faster pool servers, more memory, much faster CR destination machine with ZFS. Running XCP 8.3 (March 2026 updates) and XO (master a2e33). Replication is leaving many attached to control domain every day with NBD connection set to 2. Changing it to 1 seems to resolve the issue (no more stuck to control domain).

@Pilow We tried that as well, same problem Also tried with a VM on the same newtork, just another VLAN, and we're seeing the same thing. At first we figured it was because one of the xcp-ng's was on a remote site which is connected through an IPSEC VPN, but that wasn't the case.

@Dezerd you just have to start-copy the Replica VM it permits the original job to keep replicating on the VM. there is no failover/failback mecanism AFAIK if you work on replica started VM, you will have to put up in place a replica going to original hosts

png @florent

@MajorP93 said: -disable HA on pool level -disable load balancer plugin -upgrade master -upgrade all other nodes -restart toolstack on master -restart toolstack on all other nodes -live migrate all VMs running on master to other node(s) -reboot master -reboot next node (live migrate all VMs running on that particular node away before doing so) -repeat until all nodes have been rebooted (one node at a time) -re-enable HA on pool level -re-enable load balancer plugin Never had any issues with that. No downtime for none of the VMs. update time again. and same issue I followed these steps -upgrade master -upgrade all other nodes -restart toolstack on master -restart toolstack on all other nodes -live migrate all VMs running on master to other node(s) -reboot master now cant migrate anything else. live migration : NOT_SUPPORTED_DURING_UPGRADE warm migration: fails and VM shuts down immediately and needs to be forced back to life CR backup to another server : NOT_SUPPORTED_DURING_UPGRADE

@olivierlambert done.

@Pilow While that could be true only 1 vm was shuffled to another SR. But all VMs now being backup with CBT enabled. Well... i just check again at backups and after the last scheduled backup at 1am all vms fell back to full backup again.

@florent XO also can't migrate a VM to a new pool with a CD in the drive... It does generate an error, but the error is unclear.

@florent One last update. I reverted to Master branch (6699b) yesterday evening and the backup ran without issues overnight.

502 is an answer coming from your S3, telling the server is having an issue. Adding @florent in the loop

@simonp I'm not sure which one as I can see 2 config.tom file. 1st is under "/root/.config/xo-server/" config.toml.txt 2nd is under "/opt/xo/xo-server/" config.toml2.txt Both config.toml attached. Thank you. Best regards, Azren