Activated my GL-Inet router realized it is a small computer always on and always connected with storage expansion capabilities.
Granted is low power and is not subjected to regular backups. But for my very modest needs, basically running a bash script enhanced by some Lua calls at regular intervals, speed is not a concern. Backup may be fixed with another script.
Is anyone using their router as a nano server of sorts?
Of course. Linux is linux. As long as you have the needed packages available, go for it.
Any backup solution worth mentioning?
tar should be sufficient.
Please keep in mind that every firmware update will remove all data (and settings) not mentioned in the /etc/sysupgrade.conf
Thanks for the reminder. I assume anything on external storage (USB key and/or SD card) won’t be touched.
Tbh I would not bet on it but I didn’t try it.
Better to exclude the path than getting the drive wiped.
When i was intern at a IT bussiness a long time ago, they used a construction with samba net shares.
The beauty is, that some of these backup solutions like acronis as a example can have support of net shares.
Samba is easy to get as package for OpenWrt, and it seems the most simple one, im not aware of a package which supports this fully fledged as one solution though.
Though if you go with samba expect some decent performance hit, samba is pretty utilising 
Router space is often not sufficient, even if you take a flint 2, emmc is not designed for this, but a external drive is not bad perse to use.
Never considered Samba. But no, is not worth it for my script and tiny gdbm database. Also have plenty of unused USB keys. About the latter: should I expect any corruption issues? Their file system was not designed for continuous use perhaps.
Context? Backup for what?
Good question. Excluding the OS not much. Script is in my git already. So only log file and local gdbm. Nothing really. So not an issue. I can simply copy them anywhere at regular intervals.
CPU base load is 20% and RAM is about the same. While streaming may be more but that’s about it. We are not loading it with a VPN or anything taxing. I expect smooth ops with the dual core CPU even during the few seconds of the script running. Anything I should be aware of in this regard?
No, just use the device. Unless you are saturating CPU or IO causing its routing performance to suffer, the kernel should manage whatever you throw at it.
I use my X3000 as a NAS and media server:
I just use SAMBA filesharing and mini-DLNA as a media server (there’s a Roku on my TV). FWIW, I also host an html speedtest app on my X3000 as well so that I can check device-to-router speeds.
I use a powered USB hub plugged into the X3000 'cause the SSD doesn’t have external power and I do occasionally plug in other drives/thumbdrives as well. The USB2 port on the X3000 does kinda limit speeds on my SSD, but the max 480Mbps is okay-ish for my usecase.
The HDDs are only powered-on when I need them. As far as backups, they’re done with rsync; as my data doesn’t change too often anyway, I manually kick off a sync it 3-4 times per month which is fine for me.
The only frustrating thing with the GL-iNet firmware is that it mounts drives as disk1_part1 etc and on reboot it randomly switches the disk number when you have multiple drives. I ended up writing a hotplug.d script to remount partitions based on the partition label.
Oh - this setup is in my RV. The router is on 24/7, even while travelling. A media server is important to me as I don’t always have access to internet (and even when I do have internet, it isn’t always great). Best thing is that it all runs off of 12V DC and consumes ~15 watts per hour (not including the HDDs).
Impressive as it is I couldn’t repress the feeling of great distance between your solution with X3000, six long antennas and all, for an RV and our MT1300, one of the smallest travel routers, for our entire home. Different needs indeed.