ReadyNAS NV+ (sparc) - OS Partition 100% - How to Fix

See below:.... looks like /var/log/

DelphiNAS:~# du -csh /var/*
192k /var/backups
99M /var/cache
32k /var/ftpd
36M /var/lib
16k /var/local
32k /var/lock
1.3G /var/log
16k /var/mail
16k /var/netatalk
16k /var/opt
3.4M /var/run
544k /var/spool
16k /var/tmp
32k /var/www
48k /var/yp
1.5G total

DelphiNAS:~# du -csh /var/log/*
16k /var/log/auth.log
944k /var/log/cron.log
32k /var/log/cups
179M /var/log/daemon.log
16k /var/log/ddns
1.2M /var/log/debug
16k /var/log/dmesg
768k /var/log/exim
63M /var/log/frontview
10M /var/log/kern.log
16k /var/log/ksymoops
6.1M /var/log/LeafP2P.log
11M /var/log/messages
80k /var/log/mt-daapd.log.old
16k /var/log/ntpstats
16k /var/log/proftpd.log
1.3M /var/log/samba
16k /var/log/squeezecenter
186M /var/log/syslog
854M /var/log/upnp-av.log
800k /var/log/upnp-av.log.old
16k /var/log/user.log
1.3G total

What next? Remove the upnp-av.log? Any others?