Replication. Snapshot does not exist on the system. So cannot use it

riceru · May 5, 2026, 9:38pm

I’ve performed several replications. I’ve encountered some errors due to network outages, which I resolved by deleting the latest snapshot. The problem is that now I’m constantly getting an error that I don’t know how to fix.

[29/Apr/2026 18:18:06] ERROR [smart_manager.replication.sender:79] Id: a8c07302-2bf56a42-561e-4a2a-b3d9-f082fdd25df1-5. b'Snapshot(/mnt2/rockstor-datos.snapshots/bbg-duplicati/bbg-duplicati_5_replication_56) does not exist on the system. So cannot use it.'. Exception: b'Snapshot(/mnt2/rockstor-datos.snapshots/bbg-duplicati/bbg-duplicati_5_replication_56) does not exist on the system. So cannot use it.'

But when I look at the snapshots, I see that the bbg-duplicati_5_replication_56 snapshot is there.

# ls -la /mnt2/rockstor-datos/.snapshots/bbg-duplicati/
total 0
drwxr-xr-x 1 root        root        186 Apr 29 18:18 .
drwxr-xr-x 1 root        root        638 Mar 30 20:20 ..
drwxr-x--- 1 bbgVolcado bbgVolcado  30 Apr 14 23:18 bbg-duplicati_5_replication_56
drwxr-x--- 1 bbgVolcado bbgVolcado  30 Apr 14 23:18 bbg-duplicati_5_replication_58
drwxr-x--- 1 bbgVolcado bbgVolcado  30 Apr 14 23:18 bbg-duplicati_5_replication_63

# btrfs-list --show-id --show-parent /mnt2/rockstor-datos
WARNING: to get refer/excl size information, please enable qgroups (btrfs quota enable /mnt2/rockstor-datos)
NAME                                                                               ID PARENT    TYPE     EXCL  MOUNTPOINT
rockstor-datos                                                                      -      -      fs    4.43T (raid1, 8.30T/12.73T free, 65.15%)
   [main]                                                                           5      - mainvol       -  /mnt2/rockstor-datos
   bbg-duplicati                                                                 827      5  subvol       -  /mnt2/bbg-duplicati
      .snapshots/bbg-duplicati/bbg-duplicati_5_replication_56                  1516      5  rosnap       -
      .snapshots/bbg-duplicati/bbg-duplicati_5_replication_58                  1541      5  rosnap       -
      .snapshots/bbg-duplicati/bbg-duplicati_5_replication_63                  1556      5  rosnap       -

I can’t find anything related to the error in journalctl.

What can I do to get the replications working again?

Thank you

Hooverdan · May 6, 2026, 8:16pm

@riceru hello again.

Could you run this command:

btrfs subvolume /mnt2/rockstor-datos.snapshots/bbg-duplicati/bbg-duplicati_5_replication_56 show

In the coding there seems to be a a condition where the btrfs subvolume <mount point> show command is used to check for this.

Though i am wondering whether the deletion of the last snapshot has caused some chain reaction that the coding for _refresh_rt is not ready to handle.

github.com/rockstor/rockstor-core

src/rockstor/smart_manager/replication/sender.py

fd8f1bc53


      
                  share_path, self.max_snap_retain, regex="_replication_"
              )
              if oldest_snap is not None:
                  logger.debug(f"Id: {self.identity}. Deleting old snapshot: {oldest_snap}")
                  self.msg = f"Failed to delete snapshot: {oldest_snap}. Aborting.".encode(
                      "utf-8"
                  )
                  if self.delete_snapshot(self.replica.share, oldest_snap):
                      return self._delete_old_snaps(share_path)
          
          def _refresh_rt(self):
              # for incremental sends, the receiver tells us the latest successful
              # snapshot on it. This should match self.rt in most cases. Sometimes,
              # it may not be the one refered by self.rt(latest) but a previous one.
              # We need to make sure to *only* send the incremental send that
              # receiver expects.
              self.msg = "Failed to validate/refresh ReplicaTrail.".encode("utf-8")
              if self.rlatest_snap is None:
                  # Validate/update self.rt to the one that has the expected Snapshot
                  # on the system.
                  for rt in ReplicaTrail.objects.filter(

If I read it correctly, you should get this message, if the Rockstor database say “I got the snapshot” but the file system (on the receiving side) says “I can’t find it”.

If the database says “I can’t find it”, and the file system does “have it” (or even if it doesn’t), the message would be No succeeded trail found for ...

But I might have this backwards.

Hooverdan · May 6, 2026, 8:17pm

Either way, I suspect you might need to force a full replication again. But maybe @Flox or @phillxnet can confirm that.

riceru · May 8, 2026, 6:44am

@Hooverdan, thanks for your help.

Before reading your comments, I was running some tests and accidentally deleted snapshot 56. I’m going to have to do a full replication again.
I’ll keep this thread open and update it with the results of the replication, whether it completes successfully or the error occurs again.

Thanks