XCP-NG Delta Backups

IanMcLachlan · December 20, 2024, 9:07am

Hi Guys,

I’m trying to modify my delta backups so that I do a full backup at a particular time of the day. So my full backup interval is set at 5. I want to run deltas at 8am, 11am, 2pm, 5pm and do a full at 12am daily. However, I’ve not found a way of working it so that a full kick’s off at 12am. I thought that if I modified the backup after 5pm and save, that a full might kick off because of the change - which of course would be 12am.

How are you guys managing this?

Appreciate it.

** Should of mentioned, on latest community XO as of today.

LTS_Tom · December 20, 2024, 10:28am

I have my delta jobs separate from the full backup jobs.

IanMcLachlan · December 20, 2024, 10:42am

Hi Tom,

Not sure I follow. Do you mean you are running deltas on one schedule and full on another inside same backup job?

If so, couple of follow up questions (sorry)

does the full backup constitue as part of the delta chain?
How do you stop the detta doing a full due to having to set a full interval?

Perhaps, I’ve got the wrong end of the stick.

Thanks for you help

LTS_Tom · December 21, 2024, 1:42pm

No, full backups are full backups and dela backups are delta. These are separate jobs. A delta backup forms a chain and require full integrity of the chain to work. Under advanced in the delta backups you can choose how often you want it to rebuild the chain with a full.

github.com

vatesfr/xen-orchestra/blob/master/docs/docs/incremental_backups.md

# Incremental Backups (formerly: Continuous Delta backups)

You can export only the delta (difference) between your current VM disks and a previous snapshot (called here the _reference_). They are called _continuous_ because you'll **never export a full backup** after the first one.

## Introduction

Full backups can be represented like this:

![](./assets/nodelta.png)

It means huge files for each backup. Incremental backups will only export the difference between the previous backup:

![](./assets/delta_final.png)

You can imagine making your first initial key(complete) backup during a weekend, and then only delta backups every night. It combines the flexibility of snapshots and the power of full backups, because:

- delta are stored somewhere else than the current VM storage
- they are small
- quick to create
- easy to restore

This file has been truncated. show original

IanMcLachlan · December 21, 2024, 3:35pm

Hi Tom,

Thanks the reply.

The full integrity part of the delta (ie when it does a full backup) I want this to always run at 12am. Reason is it backups to a Minio instance on Truenas in my house and the line is less busy. So it would look something like this:

Daily

8am delta (changes) eg. 5gb
11am delta (changes) eg. 7gb
2pm delta (changes) eg. 2gb
5pm delta (changes) eg. 6gb
12am delta (full) eg. 250gb

This is one delta backup job.

Sorry, I hope this explains it a little better.

Appreciate your help

IanMcLachlan · December 21, 2024, 3:53pm

I’ve got a work-around. I create an exact new delta backup after 5pm, so this first time it runs (12am) it does a full, due to it being new. Setting the backup interval to 5 means it will always do the full at 12am based on the deltas above. Not sure if there is a way to modify an existing job.

Many thanks