Jenkins -- No space left on device

I am running a build on Jenkins and I get:

No space left on device

But when I do df, I get:

Filesystem       1K-blocks     Used Available Use% Mounted on
/dev/mapper/ROOT  19249724 18267492      4380 100% /
udev               1457152        4   1457148   1% /dev
tmpfs               587000      372    586628   1% /run
none                  5120        0      5120   0% /run/lock
none               1467496        0   1467496   0% /run/shm
/dev/sda1          1051824   107232    891984  11% /boot
/dev/mapper/AUX  129379040   210004 122596952   1% /aux

Why am I getting no disk space left?

because :

/dev/mapper/ROOT  19249724 18267492      4380 100% /
1 Like

Ok how do I give it more space? Novice here. Thanks so much.

As root, you can try to identify which are the big files (more than 20M) filling the filesystem / by running as root (assumin the size of the file is in the 7th columns otherwise, adapt the code to your own needs):

find / -xdev -type f -size +20000000c -ls 2>/dev/null| sort -k 7n

If it's a file still in use, deleting it won't remove it.