Bup – towards the perfect backup

http://wrouesnel.github.io/articles/bup%20-%20towards%20the%20perfect%20backup/

by hachiya • 12 years ago

287 96 12 years ago

wrouesnel.github.io

keehun2• 12 years ago

This seems like a fantastic tool, and I would love to try this out. And, it's free!

My personal obstacle in using a tool like bup is the back-up space. I could definitely use this for on-site/external storage devices, but I also like to keep online/cloud copies. I currently use CrashPlan for that which affords me unlimited space. If CrashPlan would let me use their cloud with bup, wow, I would switch in a heartbeat. Perhaps cloud backup tools could learn some tricks from bup.

cpach• 12 years ago

You might want to have a look at Tarsnap: https://www.tarsnap.com/efficiency.html

keehun2• 12 years ago

Aware of Tarsnap and looks very attractive. I'd rather pay a flat-rate out because I store a lot of video (Musician) and other large files. I have about 750GB pre-deduplication stored. That's a lot more $ when I go to Tarsnap.

zanny• 12 years ago

If you want a fantastic graphical frontend for bup, there is kup, which is a kde app: http://kde-apps.org/content/show.php/Kup+Backup+System?conte...

It is really easy to set up what folders to backup and where, and I use it whenever a backup is simply take all files from X, do the rolling backups at Y, and done.

rcthompson• 12 years ago

If you're considering using it, keep in mind the limitations: https://github.com/bup/bup/blob/master/README.md#things-that...

The one most likely to be a showstopper seems to be: "bup currently has no way to prune old backups."

Smudge2• 12 years ago

I can see how this would be theoretically possible in the same way I could see using `git filter-branch` to remove one or more commits from a code repository. But as it requires walking back up the tree to recalculate all of the commit hashes based on the new state of your files, I suspect it would be an extremely slow/expensive operation in bup's case. Someone who knows more about bup's internals can correct me if I'm wrong.

anoother• 12 years ago

Isn't this exactly what Obnam does?

lelutin6• 12 years ago

true. and actually bup can't use git's tooling directly because of the different use cases it's optimized for. git won't make any use of bup's optimizations: midx (combination of multiple .idx files into a handful of bigger ones to reduce page faults during binary searches) and bloom filter.

git's tools, namely filter-branch and gc have been reported to work on limited-size bup repositories, but it very quickly eats up all ram and cpu and never finishes because of the sheer amount of objects that are usually stored in a bup repository

0x0• 12 years ago

This looks very interesting as a replacement for rdiff-backup. Hopefully the missing parts aren't too far away (expire old backups, restore from remote).

mynegation• 12 years ago

Deleting old backups and the lack of encryption is what stopped me from using bup.

ars2• 12 years ago

And the reason they are not in bup is that those two things are the only hard things in a backup.

So they did the easy parts and skipped the hard parts.

Hardly a perfect backup.

I'm not sure a backup with all three of: delete old backups, encryption, and upload only differences even exists.

I think it might be one of those "pick any two" things, but if anyone knows of a backup with all three let me know.

cperciva3• 12 years ago

Tarsnap does all of these.

lelutin6• 12 years ago

some ppl have already started working on this and there's been activity on the mailing list lately about this topic.

however it's a dangerous feature to add in (backup tools should never screw up their storage, and this feature goes and removes things) so a lot of care is needed.

the boring answer is: it's coming, and we need a lot of help for vetting patches and testing them out.

metrix• 12 years ago

I think naming backups and archiving the old files should be separate applications - that could be generic to whatever backup tool you decide to use.

fragmede• 12 years ago

That is a dataset which is already deduplicated via copy-on-write semantics (it was not using ZFS deduplication because you should basically never use ZFS deduplication).

Can someone more experienced with ZFS say why?

mgbmtl• 12 years ago

I'm not an expert by any means, but the most cited reasons are that it requires a very big amount of ram, and it depends a lot (obviously) on the type of data.

timewasted• 12 years ago

In addition to the memory requirements, I seem to recall that it works at the block level, as opposed to the file level. So you could have two of the same file, but maybe one copy is written at the start of a block and one is written in the middle of a block. Same file, different blocks, so no deduplication.

aidenn03• 12 years ago

"Basically never" is an overstatement, but it is true to the point of "Never unless you already know why I said 'basically never'"

It boils down to the fact that ZFS maintains a mapping from hashes to LBNs. This allows write-time deduplication (as opposed to a scrubber that runs periodically and retroactively deduplicates already written blocks). This is somewhat memory intensive though. For smaller ZFS pools you can get away with just having lots of RAM (and with or without dedupe ZFS performs better the more RAM you have). For larger ones, you can add a SSD to act as additional disk cache.

Here's a quick description of that setup:

https://blogs.oracle.com/brendan/entry/test

Note in this example that they were already showing 128GB of RAM for a 17TB pool; the L2ARC was to augment that. In general, ZFS was designed with a much higher RAM/Disk ratio than a workstation typically has.

pwildani• 12 years ago

ZFS is also very far away from the state of the art in online dedup. For instance, http://users.soe.ucsc.edu/~avani/wildani-icde13dedup.pdf has a theoretical dedup regime that needs only 1% of the RAM for 90% of the benefit.

eli2• 12 years ago

Is there an easy way to have the backups encrypted at rest? That's a nice feature of Duplicity. I don't have to worry about someone hacking my backup server or borrowing my USB drive having access to my data.

lelutin6• 12 years ago

currently bup doesn't implement encryption (since it's a pretty hard feature to get right and we do want to finish coding other key features -- like old backup removal -- before we get to that)

some ppl have reported using an encrypted storage backend like ecryptfs to store their bup repositories in. that option shouldn't be too hard to put together.

eli2• 12 years ago

Makes sense, I'd probably prioritize pruning old backups first too. bup looks quite cool regardless, I'll be keeping an eye on it.

I like & use Duplicity, but it's a little finicky to set up right and some of the more obscure features are counterintuitive or even broken.

mappu6• 12 years ago

A shoutout for attic https://attic-backup.org/

Attic is one of the new-generation hash-backup tools (like obnam, zbackup, Vembu Hive etc). It provides encrypted incremental-forever (unlike duplicity, duplicati, rsnapshot, rdiff-backup, Ahsay etc) with no server-side processing and a convenient CLI interface, and it does let you prune old backups.

All other common tools seem to fail on one of the following points

- Incremental forever (bandwidth is expensive in a lot of countries)

- Untrusted remote storage (so i can hook it up to a dodgy lowendbox VPS)

- Optional: No server-side processing needed (so i can hook it up to S3 or Dropbox)

If your backup model is based on the old' original + diff(original, v1) + diff(v1, v2).. then you're going to have a slow time restoring. rdiff-backup gets this right by reversing the incremental chain. However, as soon as you need to consolidate incremental images, you lose the possibility of encrypting the data (since encrypt(diff()) is useless from a diff perspective).

But with a hash-based backup system? All restore points take constant time to restore.

Duplicity, Duplicati 1.x, and Ahsay 5 don't support incremental-forever. Ahsay 6 supports incremental-forever at the expense of requiring trust in the server (server-side decrypt to consolidate images). Duplicati 2 attempted to move to a hash-based system but they chose to use fixed block offsets rather than checksum-based offsets, so the incremental detection is inefficient after an insert point.

IMO Attic gets everything right. There's patches for windows support on their github. I wrote a munin plugin for it.

Disclaimer: I work in the SMB backup industry.

photoGrant• 12 years ago

For someone like me who isn't very technically minded (forgive me)...

Could you or someone explain why these fantastic sounding tools don't get a developed front-end? Or if they do why am I missing them?

The best solution I've found is ChronoSync.

aidenn03• 12 years ago

Because (for the most part) non server-admins don't do backups. It's like flossing; everybody knows you should do it, but nobody actually does it.

lelutin6• 12 years ago

as is the case with most 100% volunteer-based free software: lack of time and/or ppl to help.

There are currently multiple interfaces available to bup, but each one has some quirks. bup's web interface is still very embryonic and would need the magic touch of some designers / integration specialists to make it fun to work with.

michaelbuckbee• 12 years ago

You might want to checkout Arq from Haystack software - http://www.haystacksoftware.com/arq/ - bring your own storage, GUI client, but with open source client in case they disappear, good support, etc.

rakoo5• 12 years ago

For bup, there is something called Kup (http://kde-apps.org/content/show.php/Kup+Backup+System?conte...), but I haven't tested it.

For duplicity, there is a quite good ui in the form of deja dup (see http://www.howtogeek.com/108869/how-to-back-up-ubuntu-the-ea...). It's really nice and easy to use, and if I recall correctly it's installed by default on Ubuntu.

wvh• 12 years ago

Being interested in Linux/Unix, file systems, crypto or whatever other technical topic doesn't necessarily mean you are also interested in developing graphical interfaces. That's an art form and discipline in itself. I suppose the people who make these tools are more interested in the tools' respective technical aspects than in interface or graphical design.

Moreover, many of these backup tools run on servers (or as an automated background process) where a graphical interface is more of a handicap than an asset.

I think that in open-source software "pretty interface" sounds often like "customer-oriented" which in turn sounds like "getting paid".

sciurus• 12 years ago

How does attic compare to obnam?

mappu6• 12 years ago

I haven't used obnam much, the feature sets are quite similar, perhaps someone else can chip in here.

My personal choice of attic over obnam was based on this performance comparison[1]

1. http://librelist.com/browser//attic/2014/1/31/attic-vs-obnam...

rsync4• 12 years ago

From: https://attic-backup.org/quickstart.html#quickstart

"Attic can initialize and access repositories on remote hosts if the host is accessible using SSH."

Fantastic. Will work perfectly here. We[1] are happy to support this just like we've supported duplicity all of these years. EDIT: appears obnam also works over plain old SSH. Can't tell about zbackup, however...

As always, email us to discuss the "HN Readers" discount.

[1] rsync.net

kijin3• 12 years ago

Sorry, but "Untrusted remote storage" and "No server-side processing" are exactly the opposite of what I need.

If the original box is ever compromised, I don't want the attacker to gain any access to the backup. If you use a dumb storage like S3 as your backup server, you need to store your keys on the original box, and anyone who gains control of the original box can destroy your S3 bucket as well. Ditto for any SSH-based backup scheme that requires keys to be stored on the original box. A compromised box could also lie about checksums, silently corrupting your backups.

Backups should be pulled from the backup box, not pushed from the original box. Pushing backups is only acceptable for consumer devices, and even then, only because we don't have a reliable way to pull data from them (due to frequently changing IP addresses, NAT, etc).

The backup box needs to be even more trustworthy than the original box, not the other way around. I'm willing to live with a significant amount of overhead, both in storage and in bandwidth, in order not to violate this principle.

The backup box, of course, could push encrypted data to untrusted storage, such as S3. But only after it has pulled from the original box. In both cases, the connection is initiated from the backup box, not the other way around. The backup box never accepts any incoming connection.

Does Attic support this kind of use case? The documentation doesn't seem to have anything to say about backing up remote files to local repositories. I don't see any reason why it won't be supported (since rsync does), but "nominally supported" is different from "optimized for that use case", and I suspect that many of the latest generation of backup tools are optimized for the opposite use case.

wmf• 12 years ago

What about append-only remote storage? This is possible (in a kludgy way) in S3: http://stackoverflow.com/questions/10592541/amazon-s3-acl-fo...

mappu6• 12 years ago

By pulling backups, you're giving the backup box full control over your computer, meaning that yes it must be more trustworthy. Push backups can indeed allow the initiator to wreck the remote state.

But in the modern commercial market, who are you going to trust as your backup box provider? A USA company subject to NSLs? Run your own in a rack somewhere? Having an untrusted server greatly decreases cost and increases the chance that you can actually produce a successful backup infrastructure at all.

It is possible to do it safely.

Since you say you're "willing to live with a significant amount of overhead", i would suggest a two-tier push/pull configuration. Desktop pushes to site A; then site B pulls from site A. This also increases redundancy and spreads out the attack surface.

Append-only is another good solution - i don't believe attic formally supports this today but it should be as simple as patching `attic serve` to ignore delete requests. Good first patch.

(Also if you really trust your backup server, then you don't need encryption anyway and can just run rdiff-backup over ssh.)

corford2• 12 years ago

I use duplicity + rsync.net and have wondered about this attack vector. My solution (which admittedly only protects against remote backups being deleted by an attacker, not read) is:

1. Use sub accounts on rsync.net so backups from different parts of the system are isolated from each other.

2. Use a different GPG keypair and passphrase for each host being backed up.

3. Have an isolated machine out on the internet somewhere (that, importantly, isn't referenced by anything in the main system including documentation / internal wikis i.e. so the attackers don't know it exists) that does a daily copy of the latest and previous full backup plus any current incrementals directly from rsync.net's storage. This way I'm still covered (and can restore relatively quickly) if an attacker gets in to the system and deletes the rsync.net hosted backups for lulz.

If you're truly paranoid or need to protect backups going back over months you could also introduce a final routine that duplicates the data from the ghost machine to Amazon glacier (and then optionally pay for an HDD to be shipped periodically to your offices).

res0nat0r• 12 years ago

You could use versioned buckets in S3 and also enable MFA delete.

rsync4• 12 years ago

I really try to restrain myself when a backup article pops up on HN, but there are two things you raise here that I'd like to address ... first:

"Ditto for any SSH-based backup scheme that requires keys to be stored on the original box. A compromised box could also lie about checksums, silently corrupting your backups."

This is a good thought - you should indeed be thinking about an attacker compromising your system and then using the SSH keys they find and wiping out the offsite backup. All they need to do is look into cron and find the jobs that point to the servers that ...

So how do we[1] solve this ? All of our accounts have ZFS snapshots enabled by default. You may not be aware of it, but ZFS snapshots are immutable. Completely. Even root can't write or delete in a snapshot. The snapshot has to be deliberately destroyed with ZFS commands run by root - which of course, the attacker would not have access to. It's a nice safety net - even if your current copy is wiped out, you have your ZFS snapshots in place.[2]

"Backups should be pulled from the backup box, not pushed from the original box."

This was the tipping point - I had to comment. Since day one, we have, free of charge, set up "pull jobs" for any customer that asks for it. Works just like you'd like it to on whatever schedule they can cram into a cron format. It's a value add we've always been happy to provide.

[1] You know who we are.

[2] Yes, if you don't notice for 7 days and 4 weeks that the attacker has wiped you out, at that point your snapshots will all rotate into nothingness as well. Nothing's perfect.

dunham• 12 years ago

If you use a dumb storage like S3 as your backup server, you need to store your keys on the original box

I believe this isn't strictly necessary if you use asymmetric cryptography (e.g. curve25519). For a file, generate a temporary key pair, use it and the backup's public key to encrypt the file, then throw out the private key and send the encrypted file + public key to the server.

Apple uses this technique to move files to the "Accessible while unlocked" state without having the key for that state (i.e. while the device is locked).

hobarrera2• 12 years ago

Indeed, that's exactly what I do (with a small script that wraps rsync): the backup server PULLS data from my machine, and saves incremental backups (uses hardlinks, see --link-dest). In case my machine is compromised, the backup server is still inaccesible.

wglb• 12 years ago

Which is why tarsnap says about your keys: STORE THIS FILE SOMEWHERE SAFE! Copy it to a different system, put it onto a USB disk, give it to a friend, print it out (it is printable text) and store it in a bank vault — there are lots of ways to keep it safe, but pick one and do it.

witten3• 12 years ago

If someone is looking at trying attic and wants something a little nicer to configure and run than the very basic shell script from attic's Quick Start[1], check out the wrapper script I wrote to make this a little easier[2]. It's still somewhat "1.0" right now, but it does the basics for me. See the included sample config files for an idea of how the configuration works.[3]

[1] https://attic-backup.org/quickstart.html#automating-backups [2] http://torsion.org/hg/atticmatic/file/tip [3] http://torsion.org/hg/atticmatic/file/tip/sample/config

anarcat3• 12 years ago

i'm curious: why isn't this part of attic in the first place? i have been working with the bup folks for a while to try to make a similar interface, and i was wondering what was your experience with upstream...

mappu6• 12 years ago

I made my own wrapper as well: http://code.ivysaur.me/atticinst.html

Although upon reading yours, it looks they perform somewhat different tasks.

StavrosK• 12 years ago

I am also a very happy attic user and can attest to the wonderfulness that is it.

Here's a blog post about it:

http://www.stavros.io/posts/holy-grail-backups/

anarcat3• 12 years ago

from what i can tell here: https://github.com/c4rlo/attic/commit/f4804c07caac3d145f49fc... ... attic updates the atime when opening files right now... that patche fixes the problem, but i have to wonder how fast it actually and accurate is. bup has all sorts of helpers and tweaks to make it really fast, but also to ensure that it doesn't touch the filesystem while making backups.

i've been amazed to notice how all my files have atimes from july, when i stopped using rsync to make backups and switched to bup. :p

anarcat3• 12 years ago

i was wondering how this would compare with bup. so i did a very quick benchmark: http://anarcat.koumbit.org/2014-11-18-bup-vs-attic-silly-ben...

take it with a grain of salt, but i am surprised to say that attic is at least as fast as bup.

INTPenis• 12 years ago

The only point that stuck in my eye was atime modification from attic but I realized that in my environment I would have to mount all the backup clients remotely on the backup server so I can get around this by mounting sshfs with noatime.

tenfingers2• 12 years ago

Thanks for mentioning attic. Looks like an interesting project which slipped under my radar.

greensoap• 12 years ago

Given that old backups cannot be remove, isn't backuppc a better solution?

lelutin6• 12 years ago

backuppc is a mature technology and can very well be trusted for collecting backups.

there are some areas in which bup is trying to innovate in order to change how backups are considered (storage size being one of those)

jshb• 12 years ago

Can this new tool do incremental realtime disk image backup like Acronis True Image?

lelutin6• 12 years ago

do you mean something that would automatically update the backup when a file is changed on disk?

bup currently doesn't do that. but there's been some talk of using inotify or another such method of knowing exactly which files are modified when they are so that bup could instantly work on those.

in theory it should be feasible, it's not implemented yet however

williamstein2• 12 years ago

I had my Ph.D. student (Andrew Ohana) spend a while last summer implementing exactly this using python-inotify, since I wanted it to greatly improve the efficiency of https://cloud.sagemath.com, which makes very frequent snapshots. It's pretty solid and is on github: https://github.com/ohanar/bup/tree/bup-watch He's been busy with his actual math thesis work and teaching, so hasn't got this upstreamed into bup. It also depends on changes he made to bup to store the index using sqlite instead of some custom format.

rlpb4• 12 years ago

I wrote a very similar tool before I knew about bup - ddar (https://github.com/basak/ddar - with more documentation at http://web.archive.org/web/20131209161307/http://www.synctus...).

Others have complained here that bup doesn't support deleting old backups. ddar doesn't have such an issue. Deleting snapshots work just fine (all other snapshots remain).

I think the underlying difference is that ddar uses sqlite to keep track of the chunks, whereas bup is tied to git's pack format, which isn't really geared towards large backups. git's pack files are expected to be rewritten, which works fine for code repositories but not for terabytes of data.

rakoo5• 12 years ago

It's true that git's pack files are made for being rewritten, but bup doesn't do that. Every new run will create a new pack along with its .idx (which means that some packs may be quasi-empty) and the size of packs is capped at 1GB (Giga, not Gibi).

The real struggle of bup is how to know whether a hash is already stored, and how to know it screaming fast. It could be interesting to compare bup style and standard sqlite style, as you do in ddar.

Also, it seems ddar stores each object in its own file, like git loose objects. SQLite has a page [0] that compares this and storing blobs in SQLite, and I don't know what's the median size of your objects but if it's < 20k it seems to be better to just store them as blobs.

[0] https://www.sqlite.org/intern-v-extern-blob.html

rlpb4• 12 years ago

I don't know what's the median size of your objects but if it's < 20k...

I can't remember the exact number off the top of my head, but I designed the average size of each object to be much bigger - more like 64-256M than kilobytes. IMHO this works far better for backups. So I just use the filesystem to store the blobs, which I think works better.

labianchin• 12 years ago

I've been using duply http://duply.net/ for a while. It is a simple frontend for duplicity http://duplicity.nongnu.org/. I find it very easy to setup. It also provides encrypted backups trough GPG.

williamstein2• 12 years ago

I've long been a huge fan up bup, and have even contributed some code. I might be by far their single biggest user, since I host 96748 bup repositories at https://cloud.sagemath.com, where the snapshots for all user projects are made using bup (and mounted using bup-fuse).

Elsewhere in this discussion people not some shortcomings of bup, namely not having its own encryption and not having the ability to delete old backups. For my applications, lack of encryption isn't an issue, since I make the backups locally on a full-disk encrypted device and transmit them for longterm storage (to another full disk encrypted device) only with ssh. The lack of being able to easily delete old backups is also not an issue since (1) I don't want to delete them (I want a complete history), and (2) the approach to deduplication and compression in bup makes it extremely efficient space wise, and it doesn't get (noticeably) slower as the number of commits gets large; this is in contrast to ZFS, where performance can degrade dramatically if you make a large number of snapshots, or other much less space efficient approaches where you have to regularly delete backups or you run out of space.

In this discussion people also discuss ZFS and deduplication. With SageMathCloud, the filesystem all user projects use is a de-duplicated ZFS-on-Linux filesystem (most on an SSD), with lz4 compression and rolling snapshots (using zfssnap). This configuration works well in practice, since projects have limited quota so there's only a few hundred gigabytes of data (so far less than even 1TB), but the machines have quite a lot of RAM (50+GB) since they are configured for lots of mathematics computation, running IPython notebooks, etc.

tenfingers2• 12 years ago

I've also been using bup to replace (in some areas) my use of rdiff-backup.

It's a great tool, but since you contributed already, I cannot understate the importance of pruning old archives. For online/disk-based backup solutions, space is always going to run out eventually.

I'm using bup where I already know the backup size will grow in a way that I can manage for the next 1-2 years.

For "classical" backup scenarios though, where binaries and many changes are involved and the backup grows by roughly 10-20% a week due to changes alone, I have to resort to tools where I can prune old archives because I would either have to reduce the number of increments (which I don't want to do) or increase the backup space by a factor of 50x (which I practically cannot do either).

femto• 12 years ago

Is there anything out there that does continuous incremental backups to a remote location (like obnam, attic, ...) but allows "append only" access. That is, you are only allowed to add to the backup, and the network protocol inherently does not allow past history to be deleted or modified? Pruning old backups might be allowed, but only using credentials that are reserved for special use.

Obnam, attic and similar use a normal read/write disk area, without any server side processing, so presumably an errant/malicious user is free to delete the entire backup?

Negitivefrags• 12 years ago

Tarsnap.

You can create a key that has write only access for your automated backups and a different key that has full access for administrative purposes.

That is what we do anyway.

rakoo5• 12 years ago

bup does that.

uint322• 12 years ago

Like any good hacker I got tired of other solutions that didn't quite match my needs and made my own dropbox-like backup/sync using only rsync, ssh and encfs.

https://github.com/avdd/rsyncsync

Not polished, but it's working for me.

    - only runs on machines I control
    - server requirement is only rsync, ssh and coreutils
    - basic conflict detection
    - encfs --reverse to encrypt locally, store remotely
    - history is rsnapshot-style hard links
    - inspect history using sshfs
    - can purge old history

shell aliases showing how I use it are in my config repository

encfs isn't ideal but it's the only thing that does the job. Ideally I'd use something that didn't leak so much, but it doesn't exist.

rsync4• 12 years ago

How does that compare to this:

https://raymii.org/s/articles/Set_up_your_own_truly_secure_e...

uint322• 12 years ago

Same principle just different mechanics and assumptions.

I can't work (very effectively) in two places at once, so I don't need robust merging, just CYA synchronisation. Using only rsync features I can do a full 2-way rsync merge and catch potential conflicts, erring on the conservative so I have reasonable confidence I don't lose any work.

Minimal workstation dependencies: only bash, encfs, rsync, ssh, coreutils/findutils and optionally atd for automation. encfs is optional, too.

Instead of dvc-autosync and XMPP I just use periodic execution. I partition my stuff into smaller/high-frequency vs larger/lower-frequency to keep this efficient. These are triggered from bash (PROMPT_COMMAND, in the background) and recursive at (atd).

The local data is unencrypted on disk from this tool's POV. I use encfs --reverse and rsync the result. To browse the history, I combine sshfs with encfs in forward mode.

Linux only because that's what I use, but it should be possible to support OSX.

All in all I'm pleased I'm able to use such minimal tooling for such a successful result.

derekp7• 12 years ago

I was wondering if someone's done a side-by-side comparison of the various newer open-source backup tools? Specifically, I'm looking for performance, compression, encryption, type of deduplication (file-level vs. block-level, and dedup between generations only vs. dedup across all files). Also, the specifics of the implementation, since some of the tools don't really explain that too well, along with any unique features.

The reason I ask, is I had a difficult time finding a backup tool that suited my own needs, so I wrote and open-sourced my own (http://www.snebu.com), and now that some people are starting to use it in production I'd like to get a deeper peer review to ensure quality and feature completeness. (I actually didn't think I'd be this nervous about people using any of my code, but backups are kind of critical so it I'd like to ensure it is done as correct as possible).

konradb2• 12 years ago

There's http://burp.grke.org/burp2/08results1.html

franole• 12 years ago

Does anyone use zpaq[1]? It has compression, deduplication, incremental backup, encryption, backup versioning (unlike bup, with the ability to delete old ones), and its written un C++. But im not sure about performance over network and how its compare with bup or rsync.

[1] http://mattmahoney.net/dc/zpaq.html

jlebar2• 12 years ago

Adding a plug for git-annex. https://git-annex.branchable.com/

git annex is for more than just backups. In particular, it lets you store files on multiple machines and retrieve them at will. This lets you do backups to e.g. S3, but it also lets you e.g. store your mp3 collection on your NAS and then easily copy some files to your laptop before leaving on a trip. Any changes you make while you're offline can be sync'ed back up when you come back online.

You can prune old files in git-annex [1], and it also supports encryption. git-annex deduplicates identical files, but unlike Attic &co, it does not have special handling of incremental changes to files; if you change a file, you have to re-upload it to the remote server.

git-annex is actively developed, and I've found the developer to be really friendly and helpful.

[1] You can prune the old files, but because the metadata history -- basically, the filename to hash mapping -- is stored in git, you can't prune that. In practice you'd need to have a pretty big repository with a high rate of change for this to matter.

Edited for formatting.

glandium• 12 years ago

http://git-annex.branchable.com/not/

"git-annex is not a backup system."

beagle3• 12 years ago

Haven't seen this mentioned - but, since bup de-duplicates chunks (and thus may take very little space - e.g., when you backup a 40GB virtual machine, each snapshots takes little more than the actual changes inside the virtual machine), every byte of the backup is actually very important and fragile, as it may be referenced from thousands of files and of snapshots. This is of course true for all dedupping and incremental backups.

However, bup goes one step farther and has builtin support for "par2" which adds error correction - in a way, it efficiently re-duplicates chunks so that whichever one (or two, or however many you decide) break, you can still recover the complete backup.

abcd_f• 12 years ago

I saw "par2" and got all excited to see if lelutin re-implemented all the Galois field goodness from scratch, looked at the source and - no, bup merely spawns the par2 binary. Damn :)

xorcist• 12 years ago

I tried some backup software (of the rdiff variety, not the amanda variety) last year when I set up a small backup server for friends and family.

Obnam and bup seemed to work mostly the way I wanted to but obnam was by far the most mature tool, so this is what I chose in the end.

On the plus side, it provides both push and pull modes. Encryption and expiration works. The minus points are no Windows support, and some horror stories about performance. Apparently it can slow to a crawl with many files. I haven't run into that problem despite hundreds of gig in the backup set, but most are large files.

On the whole it's been very stable and unobtrusive during the time I've used it, but I haven't used it in anger yet. So a careful recommendation for obnam from me.

konradb2• 12 years ago

There's also Burp which is worth a look http://burp.grke.org/index.html

Looking at http://burp.grke.org/burp2/08results1.html it seems it can outperform Bup in some situations.

Bup – towards the perfect backup

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