@DustinB OK. I think I'm between a rock and a hard place! Thanks for the advice.

@DustinB Yes, by reducing the retention. I have thought about that but I'm afraid that the merge might happen after the backup and because there is insufficient space the backup would fail again. I don't want the system to force a full backup because I follow this backup with a mirror backup to s3 and the internet upload is limited in speed.

@DustinB These are delta backups. I'm just wondering if the delete button in the restore page is just that - delete which would break the chain or if a merge is used which would preserve the chain.

Good Morning, I am using XOCE Xen Orchestra, commit adc5b, Master, commit adc5b. I have backups failing on one of my servers because of insufficient free space on the NFS remote. If, in the backup/restore page I delete some of the older backups, will that break the chain or will it use merge to preserve the integrity of the chain?
Thanks.

@olivierlambert Sussed it! The remote storage must not contain any encrypted data using the old algorithm! That's where I went wrong I think!

I have just updated one of my xen-orchestra instances to Xen Orchestra, commit 47ee8 Master, commit 5dbb5. When I look at my s3 remote there is an exclamation mark next to the encryption icon. The mouseover tells me to create a new remote with the recommended algorithm chacha20-poly 1305. I created a new remote to the same repository, but the exclamation mark is still there. The algorithm remains at aes-256-ccm. Can you advise on how to proceed please?

@MathieuRA Thank you!

Feature Request: Would it be possible to specify a delay between "Number of retries if VM backup fails"? Last night there was an internet outage that affected many of my clients s3 backups. I noticed that the retries I had specified all happened immediately after the internet failure with no delay between them. Because the internet was not restored they all failed too. It would be good to set a delay between retries to allow time for the internet to be restored. Today I manually restarted all the failed backups.
Thanks.

@abudef Yes, data blocks is enabled on the remote.

@abudef I just had a backup failure. This triggered a full (key) backup on the next run which transferred 165GiB. When I rdpd into the vm I could see that the vm contained 345GiB of data including the system drive. I conclude, therefore that compression is working for full key backups at a ration of around 2:1.
I hope this helps.

@olivierlambert <The snapshot is deleted. You need a reference point to do differential>. So, since the snapshot is deleted, create a new one (snapshot) as part of the restore process and use that for the reference - then delete it when done.

@olivierlambert Agreed, but in the case where the snapshot has been deleted, why can't the differential restore process simply create a snapshot from the vm and use that instead?

@olivierlambert So, earlier in this thread, florent said "differential restore work by not transferring the data that the snapshot and the backup have in common, without reading any of those
it clone the last snapshot, an then revert the block changed between the older backup and the snapshot". If this is true (and I'm sure it is) why can't the differential restore system create the missing snapshot and use that to complete the differential restore?

@olivierlambert No, not recreating the snapshot from the CBT metadata but simply creating a new temporary snapshot, perform differential restore and delete the temporary snapshot when done.

@frank-s So- I have been thinking about this. If an NBT/CBT backup is set to destroy the snapshot, would it be possible to make differential restore work by having the restore process create the snapshot it needs, perform the differential restore and then delete the snapshot?

Thank you.

Thank you. Is there somewhere I can read about this instant restore feature?

@frank-s Soz - I meant differential restores...

@florent
I just did a delta backup on a small VM but chose NOT to delete the snapshot. It completed quickly and I then tried a differential restore and it worked. I also tried to do a differential restore on a delta backup made yesterday when the snapshot was deleted - this also worked. Will it be possible in the future to make differential backups work without keeping the snapshot? Is such a thing possible?
Thanks,
Frank.

I will backup again without deleting the snapshot and then attempt a differential restore.
I will update this thread when done.