Mount 128GB NFS share from an RPi 4 running DietPi 8.10.2
Try to backup the Pi 3 to the NFS share.
Expected behaviour
It backs up as usual
Actual behaviour
Reports that there is approximately 90 GB available, which is accurate, and that the backup will require about 110 GB, which shouldn’t be possible.
Extra details
Standard inclusions/exclusions. Include /mnt/dietpi_userdata, which is located on the SD card, and exclude the rest of /mnt and /media.
Going through / folder by folder with ‘sudo du -shc’ no folder is larger than 1.5 GB, for a total of about4 GB to back up. Have tried restarting multiple times, remounting the drive, and scanning the drive for errors.
Where did you mount the NFS share? Maybe somewhere in /mnt/dietpi_userdata/? Sounds like some sort of ‘loop’, it’s backing up the actual backup location?!
Good point. The NFS share is mounted at /mnt/backups. I have a couple other things mounted in /mnt, but nowhere else. No symlinks to other folders or anything like that either.
Alright, finally got a chance to try a local usb drive. Freshly formatted, it backed up without issue. Total backup size is 3.7 GB. So I’m not sure if that points to an issue with Rsync or NFS.
Interestingly, exit code 20 according to the man page means “Received SIGUSR1 or SIGINT”, here it says “SIGINT, SIGTERM, or SIGHUP”. SIGINT is the only match, which would be sent when hitting Ctrl+C keys.
Does the kernel report errors, either on DietPi client or NFS server side?
dmesg -l emerg,alert,crit,err
The backup size estimation indeed is usually much too large with an NFS target, size it adds the number of files+dirs * block size, as worst case max space the data will take. On NFS drives however, the block size is extremely large, not related to the actual target drive block size, but some transfer packet size, I think. Something we need to handle differently .
Could the SIGINT be from canceling the backup through the Whiplash menu when it says there isn’t enough space?
There are no kernel issues reported on the client or server.
I tried just running a backup and ignoring the space warning and it worked fine, coming in at 3.7 GB. A scheduled backup won’t work however, which is a bummer.
I’m not sure where the NFS logs live. I didn’t see anything in /var/logs.