Incremental Backups of Gmail Takeouts

https://baecher.dev/stdout/incremental-backups-of-gmail-takeouts/

by pbhn • 7 months ago

131 62 7 months ago

pbhn• 7 months ago

Gmail takeouts come in an arbitrarily-ordered mbox file; I wanted something a bit more backup friendly so I created a small tool for that purpose and wrote about it.

venusenvy47• 7 months ago

I've been meaning to try this tool for backing up. I'm curious if anyone else has tried this.

https://github.com/rustmailer/bichon

SanjayMehta3• 7 months ago

Serious question: have you ever needed an email from even 5 years ago?

I only save financial statements and contact information. Everything else gets deleted as soon as possible.

raybb• 7 months ago

I've enjoyed digging up an old flight itinerary to see how much I paid back in 2015 or just looking at the messages a company replied in support and realizing I'm not buying from them again because they didn't fix the problem.

mantra22• 7 months ago

Looking up how much things used to cost? I too like being depressed.

xnx2• 7 months ago

Everything else gets deleted as soon as possible.

What's the advantage to deleting? It's easy to ignore anything old and disk space is cheap. Do you delete old photos?

SanjayMehta3• 7 months ago

I've always run my own backup systems, from 150Mb QIC tape days. It became a habit to keep critical things to the minimum to reduce the number of tapes required.

As for photos, I print maybe 1 out of 100 and don't bother with the rest.

ifh-hn4• 7 months ago

My point of view is what's the advantages of keeping it?

I keep photos, though I don't keep all photos. But emails and messages? Why...

stephenhuey• 7 months ago

How strictly do you define need? I've been living as an adult long enough that there have been countless times I've searched for photos and emails from one or two decades ago. I distinctly remember the first time I met an Inbox Zero person. It was so important to her to militantly delete everything she had dealt with, and to me, the disadvantages from that practice far outweigh the advantages.

jawns• 7 months ago

Inbox Zero just means to deal with messages as they come in, then move them out of the inbox, generally to an archive section.

If she was hard-deleting everything, she wasn't just Inbox Zero, she was F---s Zero, too.

mantra22• 7 months ago

I have, but very rarely. I could count on one hand how often I’ve needed to dig back more than half a decade ago.

Back when I used Gmail I just kept everything personal and work related but when I moved away and started paying for email storage I took a different approach. It didn’t make sense for me to pay considerably more storage for something I almost never use.

I ended up backing up all of my emails outside of the last 5 years and stored them on an offline drive where I can reference them as eml files if I ever need it.

Going forward once a year I’ll export and purge the oldest year in my account.

omoikane• 7 months ago

I backed up lots of emails that I deemed precious, but I still search through email first, because sometimes it's just easier to search email than to search my backups.

Also, oftentimes I search email not so much for the content, but to find the timestamp associated with a particular event. I have had to search old email metadata a few times when I get an unexpected question related to time (for example, gmail will ask when you created the account as part of its account recovery process).

viraptor• 7 months ago

Yes, looking for old documents proving things for the government.

Brajeshwar2• 7 months ago

All the time. I read an interesting thing about someone online, and that name strikes me as someone I have interacted with. I search my email archive, then reply to that thread or start a new one to catch up. All of them have been super happy, “wow! You replied to our email from 10 years ago!”

I do have “Clean Inbox”[1] because I don’t see or interact with them, but I keep them. The only emails I see are the actionable “Unread OR Flagged.”

1. https://brajeshwar.com/2024/email/

cosmic_cheese• 7 months ago

Maybe not “need” in the strictest sense, but there have been more times than I can count where digging up old mail has either made things much faster and easier or helped me answer a random question that popped into my head about something that happened ages ago.

Old SMS, iMessage, Telegram etc messages have been useful from time to time too for similar reasons.

Both can also serve as exceptional time capsules that provide windows into past “eras” of life. I occasionally kick myself for not having archived mail and messages from a couple of defunct email addresses and chat apps… without them there’s a hole spanning a few years where visibility is limited.

ifh-hn4• 7 months ago

Seriously? I keep nothing unless I have to. No chat history no emails. Even if I did I'd never look back at them, what's the point?

nijave• 7 months ago

At least a few times a year. Usually looking for old orders either model number or "how old is this thing" or how much it cost over time

icedchai• 7 months ago

It has happened, but it's rare.

I let it pile up, rarely delete anything except marketing emails. Over 30K emails in my gmail inbox.

Fire-Dragon-DoL• 7 months ago

When I was moving to Canada I had to dig stuff back from 6 years before!

That's why I keep all of them

prmoustache• 7 months ago

Not on gmail but a company I worked for sent me my pay slips over email. While I also printed them, I also forwarded them to my private email address and kept them to this day on a separate mbox file.

Also when I can't remember the age of my nephews or the postal address of my siblings I just dig the birth / move announcements in my emails.

PunchyHamster4• 7 months ago

I routinely use it to look what a given product I bought and paid for, and by extension how old it is.

Also to reminisce how cheap stuff was.

So, yes

xnx2• 7 months ago

Unfortunately, many ecommerce sites have nerfed their receipt emails to make this information harder for you to find.

ggambetta2• 7 months ago

I switched to Gmail in 2007 or so. I used to have a gzipped mbox of my previous emails, dating back to maybe 1996 or 1997 when I got my first email account. This file was lost at some point, and I'm really sad about it. In some ways, it's like losing years and years of a journal, conversations I had with people, how I thought about the world at that age, etc. It's a huge loss to me.

About OP's tool, I also back up my Google account to an external disk periodically. Gmail is ~8 GB so it's manageable. But Google Photos is a pain. They recently removed most of the useful APIs, so AFAIK the only way to backup is via Takeout. It's terrible. Pictures in multiple albums are included as copies every time, so I had to make a script to find duplicates and replace them with symlinks. Just downloading the whole thing is a PITA (multiple 50 GB zip files). I get that Google has little incentive to make this better, in fact they might have an incentive to make it as inconvenient as possible, but I really wish they made it easier.

buu709• 7 months ago

I'm really hoping you're wrong about the removed APIs as I recently tried doing a takeout and about 1/3rd of every album I checked was missing. Was really hoping I could find another tool to get my photos downloaded and moved out/backed up.

cxr• 7 months ago

"Five years ago" was 2020. What you're asking is, "Have you, at some point in 2025, needed an email from 2019, 2018, etc. (i.e. from some time before that)?"

The answer: Yes, of course. (And I don't understand why anyone other than, say, a university undergrad or someone younger should find that answer surprising.)

ifh-hn4• 7 months ago

Near 50 and I can't say I need any email from 3 years ago; this is conservative, I'm probably ok with not needing emails from a year ago. Just like I don't need chat history either. What are you storing in your emails that you need to keep it beyond this? Genuinely interested. Genuinely have no clue why you'd be storing emails any length of time.

ifh-hn4• 7 months ago

Despite your down votes I'm completely in agreement. Emails and chat are transient and expire. Unless I need to keep it for, like you say, a good reason, then it's deleted.

SanjayMehta3• 7 months ago

The downvotes are due to my name. I have a fan club for pointing out hypocrisy in the past.

yooogurt• 7 months ago

if you want to back this file up regularly with something like restic, then you will quickly end up in a world of pain: since new mails are not even appended to the end of the file, each cycle of takeout-then-backup essentially produces a new giant file.

As I'm sure the author is aware, Restic will do hash-based chunking so that similar files can be efficiently be backed up.

How similar are two successive Takeout mboxes?

If the order of messages within an mbox is stable, and new emails are inserted somewhere, the delta update might be tiny.

Even if the order of the mbox's messages are ~random, Restic's delta updates will forego large attachments.

It would be great to see empirical figures here: how large is the incremental backup after after a month's emails. How does that compare for each backup strategy?

The pro of sticking with restic is simplicity, and also avoiding the risk of your tool managing to screw up the data.

This risk isn't so bad if it's a mature tool that canonicalises mboxes (e.g. order them by time), but seems risky for something handrolled.

Intralexical2• 7 months ago

As I'm sure the author is aware, Restic will do hash-based chunking so that similar files can be efficiently be backed up.
Even if the order of the mbox's messages are ~random, Restic's delta updates will forego large attachments.

I forget the exact number, but the rolling hashes for Restic and Borg are tuned to produce chunks sizes on the order of an entire megabyte.

Which means attachment file sizes need to be many megabytes in order for Restic to be much use, since the full chunk has to fall within the attachment. — You'd lose 0.5MB at both ends of each attachment on average, so a 5MB file would only be 80% deduped.

Nothing against Restic, but it's tuned for file-level backup, and I'm sure it wouldn't be as performant if it used chunks that were small enough to pick apart individual e-mails.

I suggested the author check out ZPAQ, which has a user-tunable average fragment size, and is arguably even simpler than Restic.

The ZPAQ file can then itself be efficiently backed up by Restic.

Brajeshwar2• 7 months ago

For emails, here is my current simple backup setup. Of course, I’m also looking to do this without having to open Thunderbird, or I might have an old laptop running it. So, work-in-progress.

For the email accounts I want a backup, I set it to spew out POP3 without doing anything (don’t mark read or delete). I set up Thunderbird with that POP3. It has a backup copy of all the emails. I’ve had searchable emails since like 2004/2005, and I’ve occasionally replied to people and gotten back in touch with very old friends from the Internet.

I saw an open-source tool sometime back (I think, here on Hacker News) that backs up your IMAP mails with a nicely done interface. That would be nice to have.

Edit: Perhaps Bichon,[1] mentioned somewhere in the other comment threads[2] was the one.

1. https://github.com/rustmailer/bichon

2. https://news.ycombinator.com/item?id=46429250

tehlike2• 7 months ago

Wouldn't it be nice if Google just dumped the takeout into a sqlite file?

jeffbee2• 7 months ago

How would that help 99.5% of their user base?

tehlike2• 7 months ago

As it currently stands, it's still not user friendly.

nothrabannosir• 7 months ago

Instead of the native format for e-mail archives? Supported by every MUA ever made? Not really, no.

PunchyHamster4• 7 months ago

absolutely not

pabs3• 7 months ago

Why doesn't Google use zip/tar of a Maildir instead? Much better format than mbox. Converting the mbox to Maildir using standard tools would work too.

Intralexical2• 7 months ago

`zpaq add archive.zpaq new.mbox -fragment 0 -method 3` is great for this. It splits the input into fragments averaging 1024 bytes in size [0], which catches up to ~90% of redundancy. The remaining ~10% is packed and compressed into 64MB (max) blocks that are added to the .zpaq.

The resulting artifact is a single .zpaq file on disk. This file is only ever appended to, never overwritten, so it plays nice with Restic's own chunked deduplication. Plus it won't flood the filesystem with inodes and it suffers less small files overhead than TFA's solution.

Granted I suspect TFA splitting on the e-mail headers may be chunking more efficiently. Though, unless I skimmed the linked GitHub too fast, it looks like TFA's solution also doesn't use any solid compression to exploit redundancy across chunks. And I trust zpaq as a general purpose tool more than a one-off just for a single use case. The code does look clean, though, nice work.

[0] Average fragment size is 1024*2^N. If the most of the data is attachments that don't change, you can probably use a higher `-fragment N` to have less overhead keeping track of hashes. `-method 3` is a good middle ground for backups. `-m5` gets crazy high compression ratios, but also crazy slow speed. Old versions of ingested files are shadowed by default; use `-all` when you want to list/extract them.

csb6• 7 months ago

Have you looked into using a full MIME/mbox parser library, e.g. GMime [0] or MimeKit [1]? Both support parsing mbox files directly, and they should be able to handle the intricacies of parsing any messages/attachments you throw at them. Then you could write out the MIME representation of each message (including any attachments) into its own file and then check for new messages. That way you can be sure each “chunk” represents a single message in its entirety. Not sure if this is any better since your solution seems to work pretty well.

[0] https://github.com/jstedfast/gmime

[1] https://github.com/jstedfast/MimeKit

marwis• 7 months ago

Isn't it easier to just backup via IMAP to maildir versioned with git?

Does takeout include any metadata not accessible via IMAP? Does it even include labels?

nutjob2• 7 months ago

I've read somewhere that a GMail user was banned or the like for using IMAP for backups, trying to find the reference...

faust201• 7 months ago

Total BS. Lots of people use Thunderbird IMAP for Gmail.

PunchyHamster4• 7 months ago

You can just unpack it to file-per-email (format used by most sane email clients). There are dozen of programs to do it, one is included in Debian (and so most other distros), called mb2md

jl6• 7 months ago

I have the same requirement and I solved it as follows:

Apply a label to emails dated after the last backup, using an “after:YYYY-MM-DD” search. Takeout then offers the option to export only that label. I do an annual backup so the amount of manual effort here is acceptable.

jsrozner• 7 months ago

What about using the Gmail API and listening for recent changes? I suppose it wouldn't be in a mailbox format that could be easily exported to another provider, though?

jclulow• 7 months ago

This is what I do! The API itself is not particularly amazing (the way it handles batch requests as a MIME multipart formatted POST body where each part is itself a HTTP request is particularly obscene).

The underlying data model is kind of OK though: messages are immutable, they get a long lived unique ID that survives changes to labels, etc. There is a history of changes you can grab incrementally. You can download the full message body that you can then parse as mail, and I save each one into a separate file and then index them in SQLite.

rigtorp2• 7 months ago

I have a tool that saves each mail as a single file using the Gmail API: https://github.com/rigtorp/gmbackup

neilv• 7 months ago

That imprecise chunking (with MD5 sums, and distributed across an FS tree, and using hash IDs, then separately storing the assembly information) seems like it would be a headache to restore, or to use with other mail programs.

An alternative idea is to properly parse it and store in smaller mbox files, such as one file month, with the idea that any month in the past usually will not change. (And if it changes because they are storing frequently changing attributes in a faux header, like an atime, then maybe strip that header.) Then your incremental `restic` backups work fine, and you can also use it easily with a variety of mail programs (MUAs, impromptu IMAP servers for migration, quick text editor, etc.).

jinnko• 7 months ago

I haven't used it for a while, but imapsync[0] still supports Gmail. With an approach like this you can regularly sync and get your messages in a standard format. Plus you don't have to wrangle those 50GB takeout dumps.

0: https://imapsync.lamiral.info/FAQ.d/FAQ.Gmail.txt

jokoon2• 7 months ago

I realized my inbox takes a lot of memory, even after a manual cleanup, it was still taking 5GB, despite regularly removing automated things and others.

I tried using takeout to have a more accurate listing. I thought I could open it with thunderbird, I failed, I then tried to open it with some python lib, also failed.

mcny• 7 months ago

Memory or storage?

5GB of storage sounds not so bad.

jokoon2• 7 months ago

after cleaning up? I don't think so

I don't know how large is a single mail without image or attachment, though

hasperdi• 7 months ago

I just setup Gmail backup the other day. Using getmail + cron. The emails get stored as maildir (1 mail = 1 file). It's incremental backup friendly

eterps• 7 months ago

Maybe this could be helpful? -> https://github.com/pimalaya/neverest

crazygringo• 7 months ago

I just use gmvault:

https://github.com/gaubert/gmvault

There's no reason to go through Takeout when IMAP exists.

WhyNotHugo• 7 months ago

Extracting the attachment will break signatures. This likely won’t be a problem for 99% or the people out there, but it’s important to be aware of the caveat.

If at some point in the future you need to prove that you received a given message, having the signatures (eg: DKIM) intact makes all the difference.

rigtorp2• 7 months ago

Better to use the Gmail API to incrementally backup your mail: https://github.com/rigtorp/gmbackup

Cockbrand• 7 months ago

Not sure if I'm missing something when I look at the discussion here, but there's Got Your Back [0], which backs up all emails in a Gmail account as .eml files.

This seems to be the easiest and most straightforward way for me.

[0] https://github.com/GAM-team/got-your-back

Incremental Backups of Gmail Takeouts

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