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Comment by deeblering4 | Hacker News Reader

I highly recommend scheduling a regular mbsync job to keep a local copy of your emails in sync with the imap server.

With this it's easy to pick up and move to a different provider or recover from outages, account closure, etc.

If you couple this with your own domain your email will be very portable.

I pay for a second inexpensive mailbox at Mailfence and sync the contents of the Fastmail account to a subfolder of the Mailfence account. There is rate-limiting involved, so my config is dialed down on "pipelinedepth" to ensure I don't hit that problem (you can easily overrun the Mailfence side pushing too much too fast). The cron runs via a unique user account on a cloud server every 4 hours using unique passwords (see below).

cron runner's ~/.mbsyncrc

    # Source
    IMAPAccount imap-src-account
    Host imap.fastmail.com
    Port 993
    User <user@domain.com>
    PassCmd "cat <redacted>/.secure/psrc"
    SSLType IMAPS
    SystemCertificates yes
    PipeLineDepth 1
    
    # Dest
    IMAPAccount imap-dest-account
    Host imap.mailfence.com
    Port 993
    User <username>
    PassCmd "cat <redacted>/.secure/pdst"
    SSLType IMAPS
    SystemCertificates yes
    PipeLineDepth 1
    
    # Source map
    IMAPStore imap-src
    Account imap-src-account
    
    # Dest map
    IMAPStore imap-dest
    Account imap-dest-account
    
    # Transfer options
    Channel mailsync
    Master :imap-src:
    Slave :imap-dest:SubFolder/
    Sync Pull
    Create Slave
    Remove Slave
    Patterns *
    CopyArrivalDate yes

Note: use the Fastmail option to set up a READ ONLY IMAP user password! (it's a really cool feature of Fastmail that many others do not support) Mailfence also has per-service passwords, set one up for IMAP as well. Do not use your main login passwords if you can avoid it - $0.02.

Nice idea to copy between imap accounts, I might set that up in addition to my local backups.

How do you like mailfence overall?

It seems just fine? As it's my secondary account it's mostly SMTP idle so I can't give an honest opinion about delivery (like emails from your bank) but it seems to be doing very well as a service. Like Fastmail, they have a detailed domain setup wizard to ensure all your DNS for SPF/DKIM/dmarc etc. is all properly configured for best results. I have no complaints for what I use it for, really. I do wish that I had finer grained app password control like Fastmail but it's not a deal killer.

I went with Fastmail as my primary due to the enhanced feature set and crazily enough - the Notes and Files feature in their mobile app. I can take a picture, toss it into that folder and get it on my desktop quicker than finding a USB cable or running a foldersync - the Notes are similar, I replaced Google Keep by just using the Fastmail Notes functionality.

I also use fastmail and I copied your config, with the only difference I'm saving in a local folder.

I'm getting this error for each email: IMAP error: unable to parse INTERNALDATE format

Do you also get that? Is this a problem?

I use this Docker image: https://github.com/JakeWharton/docker-mbsync

I am using Debian isync-1.3.0-2 and it's working - that Dockerfile shows it's using 1.3.3 and I spot a possible fix in 1.3.4 which could be related (or not, who knows). Your running mysync version might be different depending on the last time you rebuilt that running docker instance, the Dockerfile doesn't seem to pin it to a specific release version.

The Dockerfile is using Alpine Linux and the repos that it points to have already updated to isync-1.4.2 two days ago[2] - in general, I will make a guess your version of mbsync/isync has a bug? You're sort of using some random version, basically.

[1] https://sourceforge.net/p/isync/isync/ci/c8b73acad2a3c698d82...

[2] https://nl.alpinelinux.org/alpine/edge/community/x86_64/

For anyone reading mbsync(1) and getting confused now: they have renamed Master-Slave into Far-Near in the latest versions.

Which one is which?

Is Master = Far and Slave = Near? I'd lean towards the opposite but I can't tell for certain.

It looks like they did this in 1.4.0 released in February 2021, the online man page on the project website has not been updated for this new code. If you read the man page source [1], the word replacement seems to be that Far==Master and Near==Slave - the surrounding text is identical.

[1] https://sourceforge.net/p/isync/isync/ci/master/tree/src/mbs...

Are there any pros/cons to using mbsync over imapsync out of curiosity? Only ask as I've seen imapsync recommended in many places.

https://imapsync.lamiral.info/

I use a traditional local email client: macOS's Mail.app. It stores a copy of every email.

What's the point of using mbsync?

Well, if the mailbox is deleted on the server it could sync and delete everything on your mac

How do you sync back your local copy of the IMAP database? I had the problem of a misconfiguration in my email rules deleting everything older than 28 days. Not a _big_ problem due to backups, but I didn’t manage to restore those as any local restore got deleted as soon as the sync with the IMAP server started

mbsync supports syncing in both directions. In my case I have an hourly cron that syncs imap -> local.

And then if something goes wrong I make a copy of my backup, and invert the configuration to sync local -> imap.

Maybe it helps to copy the messages into a new IMAP folder before resyncing.

I have these problemes too. In my case there is no unique identifer if you abort a restore and move the files again in the "folder", which leads to duplicated emails.

In another discussion somewhere on the internet, someone mentioned using a service but I could not find any details and the person didn't reply.

The service is to send & receive email. But the storage capacity was less and the service only has a imap & smtp address and no webmail. Basically the service focuses on ensuring the emails are sent & received. The person has a webserver hosted at home that copies the emails from that server and incase of sending email, sends via that server. Then all the content of the home server is backed up at some off-site backup service.

Any idea which is the services being used and how would such a system be rated? It sounds like you are doing something similiar.

Unfortunately, you would have to trust the relay not to snoop. You might as well self host a mail server, since you can guarantee end to end encryption.

But if your primary email provider reports an empty mailbox for the synced mailbox, the backup mailbox will be cleared too?

I mean the idea is great but wouldnt you need a backup mailbox provider allowing you to restore daily snapshots?

I use offlineimap* which allows you to optionally sync in one direction.

I'm not sure what happens if the remote emails are overwritten though.

* https://github.com/samhh/dotfiles/blob/master/home/.config/o...

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