Recovering Dovecot mailboxes from disk (cPanel, Maildir format to Mbox)
I was given a backup of a hard drive containing cPanel-managed mailboxes and wanted to recover them into a readable format. When spinning up a new server using the drive backup, I could no longer access webmail or IMAP due to a cPanel license issue which I tried to work around but quickly disregarded. cPanel uses Dovecot to manage user mail.
What follows is a quick manual on how to recover and read Dovecot mailboxes given only disk access, a couple of scripts and a mail client that can read Mbox files.
We assume the mailboxes are stored in the Maildir++ format. These can be recognized by their directory structure: they always contain subdirectories cur, new, and usually tmp.
1. Find and copy the mailboxes
On my particular cPanel-managed server, the maildirs were located in /home/<user>/mail and there were also sub-maildirs in /home/<user>/mail/<domain>/<account>
Specific folders in the mailboxes used hidden directories like .Sent or .Trash.
You should be able to find maildirs by running:
find / -type d -name curCopy them all to a temporary workspace directory somewhere.
2. Unzip e-mails where necessary
I found that some of the e-mails were garbled when later converting the maildir to an mbox file.
This turned out to be because some (newer) mails were being stored gzipped.
I wrote a quick shell script to walk over all the e-mails and g-unzip them: maildir-gunzip.sh
Don’t use it on the originals, make a copy first!
To use:
chmod +x maildir-gunzip.sh # Make it executable
./maildir-gunzip.sh /path/to/copy-of-maildir3. Convert to an Mbox file
Mbox files are a convenient, and perhaps the most common format for moving mailboxes around.
There is a nice script called maildir2mbox.py which has been adapted by various people over the years.
The most recent version I could find was one by Github user bluebird75. Download the script here. (mirror)
Make sure you have Python v3 installed on your machine.
Run the script like so:
maildir2mbox -r /path/to/maildir-copy outputfile.mboxThis Dovecot docs page contains an alternative script for this written in Perl, as well as some scripts for converting between other formats.
4. Open the Mbox file
Any email client that can read Mbox files will do.
I used Evolution. In Evolution, go to File > Import and follow the steps.
Make sure you make a new directory to import in so you can easily delete the emails later.
Extracting MySQL databases from a disk backup, the easy way
A lot of guides online tell you that, if you want to restore a MySQL instance using only a backup of the /var/lib/mysql directory, you should recover/rebuild the entire operating system that MySQL ran on.
It’s true that you should mimic the original setup, but only with regards to the MySQL version and sometimes whether MariaDB or MySQL were used. Once you’ve got that, you can very easily spin the database up again using Docker. Assuming you know the database user+password, you can just run mysqldump as you normally would.
Below are the steps that worked for me.
1. Determine MySQL version
Find the location of the mysql or mariadb binary:
find /thebackup -type f -name mysql -or -name mariadbI had a rough idea of what the version would be so I ran strings and searched for 8.0:
$ strings /thebackup/usr/bin/mysql | grep '8\.0'
8.0.25
/build/mysql-8.0-eXpnQw/mysql-8.0-8.0.25/sql-common/client.cc
/build/mysql-8.0-eXpnQw/mysql-8.0-8.0.25/sql-common/client_plugin.cc
...An alternative which may work generically:
strings /thebackup/usr/bin/mysql | grep '^/build'2. Start the database in Docker
Now that we have the exact version number (8.0.25), we can spin up a Docker container for it:
docker run --rm --name mysql-recovery -v /thebackup/var/lib/mysql:/var/lib/mysql mysql:8.0.25 --skip-grant-tables --user=mysqlReplace mysql:<version> with mariadb:<version> if it’s MariaDB.
Note that we’re mounting the mysql lib directory into the container using -v. If you want to play it safe, make an extra backup of /var/lib/mysql first.
3. Extract data
You can now browse or dump the data using command-line tools:
docker exec -it mysql-recovery mysql
docker exec mysql-recovery mysqldump mydatabase > mydatabase-backup.sqlHOWTO: rtorrent + rutorrent on the Netgear ReadyNAS 102
In 14 short steps. Wonderful!
Prerequisites:
- A Netgear ReadyNAS 102 with firmware version 6.1.6 to 6.1.8, which I’ve tested this on
- Root access to the NAS. All the commands in this tutorial should be run as root
NOTE: This tutorial probably works for any system running Debian Wheezy.
6.04.14HOWTO: Unattended rdiff-backup + multiple commands
Here’s a small addition to Dean Gaudet’s tutorial on how to set up rdiff-backup for secure, unattended remote backups.
The scenario: you want host1 to pull backups from:
host2 : /var/log
host2 : /var/www
You’ve set everything up:
- A non-root user on host1 called backupuser which initiates the backup
- SSH private/public keys for backupuser
- Added backupuser’s public key to host2:/root/.ssh/authorized_keys
- An entry for host2 preconfigured in host1:~/.ssh/config as explained in the original tutorial.
Then you find out that in authorized_keys, you can only limit backupuser to run one command, not multiple:
root@host2:~# cat /root/.ssh/authorized_keys command="commandname" ssh-rsa FBwfijwefwB(...etc...)