recommendation for adjusting contents of root filesystem

[Dan Martin]

Hi All,

I recently installed a Suse SLES11 system.
I used a small boot filesystem, a "small" root filesystem (8GB), and
I used lvm2 for  /u   and   /srv  filesystems.

I limited the size of the root filesystem because I wanted to be able to
backup all of the root file system to an 8GB USB stick.

Now, usage of the root filesystem is over 90%.

The following directories all reside in the root filesystem:  
/tmp
/var
/usr

I would like to like to recursively copy one or more of  /var,  /usr,  
and  /tmp
to    /u   so that they will be on a different filesystem; then remove 
them from
the root filesystem; then   sym link them back so that they  appear in 
the same path.

Is it safe to do this?  Do I run the risk of breaking anything at boot 
time that
might be expecting a file to be available in the root filesystem?  That 
is, before
the   /u   filesystem is mounted?

Thank you,
Dan Martin