No space left on device prevents login-Collection of common programming errors

It seems that when you run out of disk space all remote logins are prevented [I’m using Red Hat 4.4]. Apparently this is because all non-superuser logins have to write to /var/log/auth.log

This is a common occurence when /var/tmp/cores gets filled due to (user) programs crashing, or a process generating tons of log (under /var/tmp).

What configuration changes can be made to prevent this occurring?

Can + do you:

• put /var/tmp on a different filesystem?
• put /var/log on different filesystem?
• enforce a strict separate of filesystems accessible user + system processes?