when setting up a unix client
the NB install puts /tmp and /proc in the exclude list by default.
it has to be in the exclude list to be excluded ( this is a file in <installdir>/netbackup)
if it is NOT in the exclude list it would get backed up - so if you modified the exclude list on the unix client and took out /tmp and /proc it would try to back the up.
the reason it tires to back them up
in unix you have filesystems ( kind of think of them as windows drives) file systems are MOUNTED on top of some place else
so say you have the file system / (slash - called root)
in / you have a dir called tmp
now a file system is created called tmp and is MOUNTED in /tmp - this now becomes a cross mount point.
if you said to yes cross mount points then when the backup does / it will get all sub dirs including /tmp that is MOUNTED there. It will then go and backup all other file systems as well including the file system /tmp - so now it has backed it up twice - this is why we say do not cross mount points by default.
if we do not cross mount points when the filesystem / is backed it will see that a filesystem has been mounted on tmp and will say "hey that is a separate file system so I will not get it now, but will get it latter"
so this would apply to all mounted file systems like var, usr, proc, opt and anything else you might have created but will skip any that are listed in the exclude file.
so /tmp and /proc should be added to the exclude list by default when you install NB on a unix client. If it is not there it will back it up.
cross mount points are backed up as separate file systems so they only get backed up once.
