You can run multiple examples of below command:
find /var/log -size +400000000c
That will look for any files bigger than 400 MBs in /var/log dir...replace 4 with any number to search for relevant size (1 for 100 MBs, 2 for 200 MBs and so on)
example from my lab (R81.20)
[Expert@QUANTUM-MANAGEMENT:0]# find /var/log -size +400000000c
[Expert@QUANTUM-MANAGEMENT:0]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_splat-lv_current 55G 16G 40G 29% /
/dev/sda2 291M 42M 235M 15% /boot
/dev/mapper/vg_splat-lv_log 60G 9.5G 51G 16% /var/log
tmpfs 7.8G 25M 7.7G 1% /dev/shm
cgroup 7.8G 0 7.8G 0% /sys/fs/cgroup
[Expert@QUANTUM-MANAGEMENT:0]#
Andy