48 lines
4.2 KiB
Markdown
48 lines
4.2 KiB
Markdown
# Backup Using Borg
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https://borgbackup.readthedocs.io/
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## Reasons I use Borg:
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- Deduplication
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- Encryption (I use BLAKE2b-256)
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- Multiple compression options (I use LZ4)
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- Easily accessible
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- FOSS
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- Preserves most file types, attributes, etc.
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- Can verify data integrity with CRCs and HMACs
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## Script Notes
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### Passphrase
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- I do NOT want the encrypted passphrase in cleartext within the script.
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- I also do NOT want to set an environment variable with env command or system() to avoid exposure in the process list.
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- Instead, I use BORG_PASSCOMMAND with a dotfile with specific permissions. 'export' in a shell script uses a process environment only accessible to that user.
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### Package Lists
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- At the moment I only use Arch and Ubuntu/Debian systems, so the package list dump only checks for these. This can be expanded as needed.
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- Since I don't backup the entire system, I'd rather just do a quick dump of packages and script a reinstall as needed.
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- This would be obsolete with Ansible (which I will ideally use later down the line).
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### Backup Locations
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- I generally do not care to backup the entire system, and only want things in /home or configs (usually in /etc)
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- I use a case statement to add or remove things as needed per system. Probably not the most efficient and it's a bit ugly, but it's very clear/easy to read, debug, and modify as needed.
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### Why do you copy files and directories to /home?
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- I'd prefer to avoid using root when possible, especially since I don't want to backup the entire system.
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- If I'm only copying /home and config files, I don't see a reason to use root, and would rather just use a local user.
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- HOWEVER, there should not be a concern with using root. The networking is done by SSH and RPC, not Borg. If there is a security concern, it would be with SSH and RPC, which is probably an acceptable risk.
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- Since I'm ideally only copying config files, there should not be an issue with duplicated space or long copy times from (example:) /etc to /home.
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- I'm also using single-user systems. If these were multi-user systems, there might be another discussion since there would need to be a "/home admin" that could access all files in /home.
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### Why do you use a locally mounted remote file system instead of Borg's client/server mode?
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- Mixture of laziness and old habits. Borg has made it easier to use client/server mode without mounting drives, and I just haven't kept up with the times.
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- I will ideally be modifying this to use client/server mode in the future.
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- Nothing particularly *wrong* with using a mount, it's just slower since every operation has to go over the network.
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### Sudo
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- If sudo is used in the backup script (like I do when stopping/starting certain services), it is recommended to put NOPASSWD for that specific command for that specific user in a /etc/sudoers.d/\<appropriately_named_config_file>
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- Putting the permissions in the sudoers.d file is recommended for a few reasons:
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1) Those config files stay on upgrades, while content added to /etc/sudoers may not
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2) PAM authentication reads and respects it. If you put the same info in just the sudoers file, PAM conversations may (and likely will) still fail
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- It is recommended to not run the entire script as sudo, and it's also recommended to give nopasswd to only specific commands and not to all sudo prompts
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## Automation
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- Automation is done with systemd, but cron can be used if preferred.
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- Change the times and users for each system. If not running as root, be sure to replace systemd unit user variables with the actual user of the system.
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- I have no need to have the drive mounted full time (backups are on NFS mounts only used for backups), so I also have systemd mount the drive for the backup, then unmount when done. Be sure to change the drive mount as well for each system.
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- For the mount service, the unit name and 'Where' setting MUST match. For example, for "Where=/mnt/mountpoint/backups", the unit must be named mnt-mountpoint-backups.mount
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- I set specific backup times in the timer unit rather than a random time +- midnight (OnCalendar=daily with a RandomizedDelaySec) so I have predictable, known times when things may be down.
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- The timer and service must have the same name (except for the .service and .timer part of course). |