I’ve started throwing some enthusiasm into my mongo db projects so I’ve decided I should start a serious backup plan for the content of the databases in it. My understanding is that this should be one of the selling points for mongo db as you can just export to json and store the file. I’m not currently trying to do anything crazy, like store images in the db (is that even possible?), so this should be straight forward.
SSH onto the box in question and run the following:
mongoexport --db <db-name> --collection <collection-name> --out output.json
mongoexport --db healthcheck --collection services --out services.json
In this database, I only have one collection (start simple), it would appear that we will have to back up each collection individually using this method. I’m ok with that for now as my databases aren’t huge. I did some reading about mongodump, which seems to be able to export the entire database with one command but there seems to be compatibility problems with older version of mongodb. As I’m currently running a relatively old version of mongodb on my pi (highest supported at the time of writing but still old), I will continue with this method.
Now store the
output.json somewhere safe and feel good about having backed up your data.
mongoimport --db <database-name> --collection <collection-name> --file input.json
mongoimport --db healthcheck --collection services --file services.json
Update on this. It looks as though the import mechanism on earlier versions of mongo db does not support the date format created in later versions of mongodb. I may have to convert them to epoch (unix time). Theoretically if you export it from the db and then import it back into that db it should work ok. I did some testing from a later version export to an earlier version import and this is where I came unstuck.
Turn it into a script
There’s no way I will remember to ssh onto this box and run this command on a regular basis so I guess we should script it.
SSH back onto your box and navigate to
Create a new script and make it executable:
sudo vi mongodb-backup sudo chmod a+x mongodb-backup
Write your script:
#!/bin/bash mongoexport --db <db-name> --collection <collection-name> --out output.json
#!/bin/bash mongoexport --db healthcheck --collection services --out services.json
Save your script
:wq and this should now run every day. You can test the script whilst you’re on the box to make sure it’s working:
Now rest easy, safe in the knowledge that your data is safe…or maybe we should backup to another device on our network in case the pi sd card corrupts? Yes…yes we should. Back into the script:
#!/bin/bash cd <backup-directory> mongoexport --db <db-name> --collection <colection-name> --out output.json rsync -ravz <backup-directory> <user>@<host>:<backup-directory>
#!/bin/bash cd /pi/home/backup-mongodbs/healthcheck mongoexport --db healthcheck --collection services --out services.json rsync -ravz /pi/home/backup-mongodbs/ firstname.lastname@example.org:/media/kodi/backup/
Ok, now we can…wait, what if that machine corrupts? I guess we have to draw the line somewhere.