To mount procfs you need to do following.

mount -t procfs proc /proc

It is necessary to run command like truss on dump(core) file.

To check network status

nload -u m <interface>

To check system statistics.

vmstat -z

OR

systat -v

To Monitor Disk activity there is command called gstat.
there is three switches. '-c' '-d' & '-I'
-c shows consumers of geom
-d shows delete operations.
-I can define interval of refresh.

gstat -I 1 -c

Most is it is usefull when you can not use crontab command.
Cron file located @

/var/spool/cron