This has been replaced with a permissions feature that still provides both delete and overwrite protections. The difference is the underlying store needs to implement it rather than running a server that understands the permission differences. You can read more about this change here: https://github.com/borgbackup/borg/issues/8823#issuecomment-...
Isn't this "no-delete permission" just a made-up mode for testing the borg storage layer while simulating a lack of permissions for deleting and overwriting? In actual deployment, whatever backing store is used must have the access control primitives to implement such a restriction. I don't know how to do this on a posix filesystem, for example. Gemini gave me a convoluted solution that requires the client to change permissions after creating the files.
at first it was implemented to easily test permission restricted storages (can't easily test on all sorts of cloud storages).
it was implemented for "file:" (which is also used for "ssh://" repos) and there are automated tests for how borg behaves on such restricted permissions repos.
after the last beta I also added cli flags to "borg serve", so it now also can be used via .ssh/authorized_keys more easily.
so it can now also be used for practical applications, not just for testing.
not for production yet though, borg2 is still in beta.
Currently, you can either provide the `BORG_REPO_PERMISSIONS` env var to borg [0] or `--permissions` flag to `borg serve` [1]. You can then enforce this as part of your `authorized_keys` command, for example.
Ah, I was searching borgstore for no-delete, but it gets exploded into itemized permissions in borg. Documentation seems to be non-existent, as the only mention seems to be the changelog where it suggests this only exists for testing. But I suppose it's not released yet.
Thanks for that link.
That issue somehow didn't come up when I researched the removal of append-only.
The only hint I had was the vague "remove remainders of append-only and quota support" in the change log without any further information.
The old append-only mode was a hack that wasn’t very useful in practice anyway, because there were no tools to dissect changes in a repository and the datastructures wouldn’t support that anyway.
Making e.g. snapshots on the backing storage was always the better approach.
I also use nginx with HTTPS + HTTP authentication in front of it, with a separate username/password combination for each server. This makes rest-server completely inaccessible to the rest of the internet and you don't have to trust it to be properly protected against being hammered by malicious traffic.
Been using this for about five years, it saved my bacon a few times, no problems so far.
We just started deploying this on rsync.net servers - which is to say, we maintain an arguments allowlist for every binary you can execute here and we never allowed 'rclone serve' ... but now we do, IFF it is accompanied by --stdio.
restic’s rest-server append-only mode unfortunately doesn’t prevent data deletion under normal usage. More here: https://restic.readthedocs.io/en/stable/060_forget.html#secu.... Their workaround is pretty weak, in my opinion: a compromised client can still delete all your historic backups, and you’re on a tight timeline to notice and fix it before they can delete the rest of your backups, too.
I use restic+rclone+b2 with an api key that can't hard delete files. This gives me dirt-cheap effectively append-only object storage with automatic deletion of soft deleted backups after X days.
I've been using btrbk with a local linux machine i use as a file server. Works well for incremental snapshot backups, no need to "unthaw" an image, I can directly fetch files from a previous snapshot. The only thing I haven't figured out with btrfs is how to efficiently handle incremental backs to S3. I guess there's not much choice than to use image diffs using btrfs-send because you don't have hard/ref links. But I don't like this because then if i want to retrieve a file from some version I'd have to have an extra 30 TB free to install the base image and progressively all the diffs up to the point I want to retrieve, seems a lot harder. So to make this reasonable I'd have to choose to make periodic non-incremental base images, starts getting complicated.
My current approach is restic, but I'd prefer to have asymmetric passwords, essentially the backup machine only having write access (while maintaining deduplication). This way if the backup machine were compromised, and therefore the password it needs to write, the backup repo itself would still be secure since it would use a different password for reading.
It seems the suggested solution is to use server credentials that lack delete permissions (and use credentials that have delete for compacting the repo), but does that protect against a compromised client simply overriding files without deleting them?
No. Delete and overwrite are different. You need overwrite protection in addition to delete protection. The solution will vary depending on the storage system and the use case. (The comment in the PR is not an exhaustive description of potential solutions)
There used to be append-only, they've removed it and suggest using a credential that has no 'delete' permission. The question asked here is whether this would protect against data being overwritten instead of deleted.
I use rsync.net for borg backups. They create daily ZFS snapshots that are read-only to the user, specifically for ransomware protection.
But this was a good reminder I should probably figure out some good way to monitor my borg repo for unintended changes. Having snapshots to roll back to is only useful if a problem is detected in time.
For low-latency storage (like file: and maybe ssh:) it already works quite nicely, but there might be a lot to do still for high-latency storage (like cloud stuff).
I used to have a BorgBackup server at home that used append-only and restricted-SSH.
It wasn't perfect, but it did protect against some scenarios in which a device could be majorly messed up, yet the server was more resistant to losing the data.
For work, the backup schemes include separate additional protection of the data server or media, so append-only added to that would be nice, as redundant protection, but not as necessary.
I've been using Borg for a while, I've been thinking about looking at the backup utility space again to see what is out there. What backup utilities do you all use and recommend?
I spent too long looking into this and settled on restic. I'm satisfied with the performance for our large repo and datasets, though we'll probably supplement it with filesystem-based backups at some point.
Borg has the issue that it is in limbo, i.e. all the new features (including object storage support) are in Borg2, but there's no clear date when that will be stable. I also did not like that it was written in Python, because backups are not always IO blocked (we have some very large directories, etc.).
I really liked borgmatic on Borg, but we found resticprofile which is pretty much the same thing (it is underdiscussed). After some testing I think it is important to set GOGC and read-concurrency parameters, as a tip. All the GUIs are very ugly, but we're fine a CLI.
If rustic matures enough and is worth a switch we might consider it.
I still use borg for local backups but use restic for all my offsite backups. Off-hand I don’t think redtic lacks any feature borg has (although there’s probably at least one) after they added compression a few years ago.
Kopia is surprisingly good. I use it with a b2 backend, had percentage based restore verification for regulatory items and is super fast. Only downside is lack of enterprise features/centralized management.
Index of files stored in git pointing to a remote storage. That sounds exactly like git LFS. Is there any significant difference? In particular in terms of backups.
Git LFS is 50k loc, this is 891 loc. There are other differences, but that is the main one.
I don't want a sophisticated backup system. I want one so simple that it disappears into the background.
I want to never fear data loss or my ability to restore with broken tools and a new computer while floating on a raft down a river during a thunder storm. This is what we train for.
Actual invocation is this huge hairy furball of an rsync command that appears to use every single feature of rsync as I worked on my backup script over the years.
Yes, this adds a couple of nice features, it is easy to go back to any version using only normal filesysem access and because they are hard links it only uses space for changed files and you can cull old versions without worrying about loosing the backing store for the diff.
I think it sort of works like apples time-machine but I have never used that product so... (shrugs)
Note that it is not, in the strictest sense, a very good "backup" mainly because it is too "online", to solve that I have a set of removable drives that I rotate through, so with three drives, each ends up with every third day.
Quite expensive, but it should only ever be a last resort after your local backups have all failed in some way or another. For $1/mo/TB you purchase the opportunity to pay an exorbitant amount to recover from an otherwise catastrophic situation.
Support for S3 means you can just have minio server somewhere acting as backup storage (and minio is pretty easy to replicate). I have local S3 on my NAS replicated to cheapo OVH serwer for backup
I've been using device mapper+encryption to backup my files to encrypted filesystem on regular files. (cryptsetup on linux, vnconfig+bioctl on openbsd). Is there a reason for me to use borgbackup? Maybe to save space?
I even wrote python scripts to automatically cleanup and unmount if something goes wrong (not enough space etc).
On openbsd I can even Double encrypt with blowfish(vnconfig -K) and then a diff alg for bioctl.
Does your solution do incremental backups at all? I have backups going back years, because through incremental backups each delta is not very large.
Every once in a while things gets sparsed out, so that for example I have daily backups for the recent past, but only monthly and then even yearly for further back.
I maintain my incremental backups and handle the rotation with a shell script (bontmia) based on rsync with `--link-dest` (it creates hard links for unchanged files from the last backup). I've been using this on top of cryptsetup/luks/ext4 or xfs for > 10 years.
Bonus: the backups are readable without any specific tools, you don't have to be able to reinstall a backup software to restore files, which may or may not be difficult in 10 years.
The purpose of the append-only feature of borgbackup is to prevent an attacker from being able to overwrite your existing backups if they compromise the device being backed up.
Are you talking about using ZFS snapshots on the remote backup target? Trying to solve the same problem with local snapshots wouldn't work because the attack presumes that the device that's sending the backups is compromised.
There's not much sense in using these advanced backup tools if you're already on ZFS, even if it's just on the backup server, I would stick with something simpler. Their whole point is in reliable checksums, incremental backups, deduplication, snapshotting on top of a 'simple' classical filesystem. Sounds familiar to any ZFS user?
Are there any good options for an off-site zfs backup server besides a colo?
Would be interested to know what others have set up as I'm not really happy with how I do it. I have zfs on my NAS running locally. I backup to that from my PC via rsync triggered by anacron daily. From my NAS I use rclone to send encrypted backups to Backblaze.
I'd be happier with something more frequent from PC to NAS. Syncthing maybe? Then just do zfs sync to some off site zfs server.
zfs.rent is in the wrong location and I can't see anything about zfs send/receive support on rsync.net. What kind of VPS product has multiple redundant disks attached? Aren't they usually provided with virtual storage?
Ideally a backup system should be implementable in such a way that no credential on the machines being backed up, enable the deletion or modification of existing backups. That's so that if your machines are hacked a) the backups can't be deleted or encrypted in a ransom attack and b)
If you can figure out when the first compromise occurred, you know that before that date the backup data is not compromised.
I guess some people might have been relying on this feature of borgbackup to implement that requirement
FYI for those using restic, you can use rest-server to achieve a server-side-enforced append-only setup. The purpose is to protect against ransomware and other malicious client-side operations.
Restic is the winner. It talks directly to many backends, is a static binary (so you can drop the executable in operating systems which don’t allow package installation like a NAS OS) and has a clean CLI.
Kopia is a bit newer and less tested.
All three have a lot of commands to work with repositories. Each one of them is much better than closed source
proprietary backup software that I have dealt with, like Synology hyperbackup nonsense.
If you want a better solution, the next level is ZFS.
You can consider something like syncthing to get the important files onto your NAS, and then use ZFS snapshots and replication via syncoid/sanoid to do the actual backing up.
Or install ZFS also on end devices, and do ZFS replication to NAS, which is what I do. I have ZFS on my laptop, snapshot data every 30 minutes, and replicate them. Those snapshots are very useful, as sometimes I accidentally delete data.
With ZFS, all file system is replicated. The backup will be consistent, which is not the case with file level backup. With latter, you have to also worry about lock files, permissions, etc. The restore will be more natural and quick with ZFS.
I can't speak to zfs but I don't find btrfs snapshots to be a viable replacement for borgbackup. To your filesystem consistency point I snapshot, back the snapshot up with borg, and then delete the snapshot. I never run borg against a writable subvolume.
I don't know about the other two but restic seems to have a very good author/maintainer. That is to say that he is very active in fixing problems, etc..
Same here: my selection boiled down to Borg vs. Restic. I started with Restic because my friends used it and, while it was perfectly satisfactory functionally, found it unbearably slow with large backups. Changed to Borg and I've been happy everafter !
Kopia is awesome. With exception to it’s retention policies, but work like no other backup software that I’ve experienced to date. I don’t know if it’s just my stupidity, being stuck in 20 year thinking or just the fact it’s different. But for me, it feels like a footgun.
The fact that Kopia has a UI is awesome for non-technical users.
I migrated off restic due to memory usage, to Kopia. I am currently debating switching back to restic purely because of how retention works.
I picked Kopia when I needed something that worked on Windows and came with a GUI.
I was setting up PCs for unsophisticated users who needed to be able to do their own restores. Most OSS choices are only appropriate for technical users, and some like Borg are *nix-only.
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