Why Is /Dev/Vda1 Getting 100%? Disk Size Is 960Gb

My Wordpress site crashed and when I logged in to the server to check, i am unable to start mysql because for some strange reason 960GB is 100% full (which shouldn't be, I don't have that much articles/images)

Here's the output of df

df

Filesystem     1K-blocks      Used Available Use% Mounted on
udev            24721432         0  24721432   0% /dev
tmpfs            4946144      8776   4937368   1% /run
/dev/vda1      975421904 975405520         0 100% /
tmpfs           24730704         0  24730704   0% /dev/shm
tmpfs               5120         0      5120   0% /run/lock
tmpfs           24730704         0  24730704   0% /sys/fs/cgroup
/dev/vda15        106858      3426    103433   4% /boot/efi
tmpfs            4946144         0   4946144   0% /run/user/0

Here's the output of

sudo find / -type f -printf '%12s %p\n' 2>/dev/null|awk '{if($1>999999999)print $0;}'
  1031798784 /var/lib/mysql/wordpress/wp_posts.ibd
  1015021568 /var/lib/mysql/wordpress/wp_postmeta.ibd
  1073741824 /var/lib/mysql/ib_logfile0
  1073741824 /var/lib/mysql/ib_logfile1
  7284850736 /var/lib/mlocate/mlocate.db

syslog

mysqld: Disk full (/tmp/#sql_721_1.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")

Please help. :(