Help with increasing file system size in Sun OS 5.9

Hi,

I have recently taken up to support these SunOS 5.9 sun4u sparc SUNW,Sun-Fire-V240 boxes and got a request to increase the size of /backup01 as its getting filled up quickly and can't play much on it as these are production servers. As I have no idea about how to do this, can anyone let me know the steps as how it can be done with best possible way. We are using mirroring here and more information below.

  bash-2.05# df -k
  Filesystem            kbytes    used   avail capacity  Mounted on
  /dev/md/dsk/d0       10327372 3293091 6931008    33%    /
  /proc                      0       0       0     0%    /proc
  mnttab                     0       0       0     0%    /etc/mnttab
  fd                         0       0       0     0%    /dev/fd
  /dev/md/dsk/d1       4133838  978091 3114409    24%    /var
  swap                 4232528     144 4232384     1%    /var/run
  swap                 4232384       0 4232384     0%    /tmp
  /dev/md/dsk/d6       41632867 35702705 5513834    87%    /db02
  /dev/md/dsk/d4       41311843 37075588 3823137    91%    /db01
  /dev/md/dsk/d5       99802704 90360658 8444019    92%    /backup01
  /dev/md/dsk/d3       10327372 3495623 6728476    35%    /opt/oracle
  nas01a:/vol/asdb
                       346030080 301001440 45028640    87%    /drnas
  nas01a:/vol/unix
                       576716800 343669576 233047224    60%    /drunix
  
 bash-2.05# metastat -p
  d6 -m d26 d16 1               /db02
  d26 1 1 c1t1d0s5
  d16 1 1 c1t0d0s5
  d5 -m d15 d25 1                /backup01      
  d15 1 1 c1t2d0s1
  d25 1 1 c1t3d0s1
  d4 -m d14 d24 1                /db01
  d14 1 1 c1t2d0s0
  d24 1 1 c1t3d0s0
  d3 -m d23 d13 1               /opt/oracle
  d23 1 1 c1t1d0s4
  d13 1 1 c1t0d0s4
  d2 -m d22 d12 1               /swap (/var/run)
  d22 1 1 c1t1d0s3
  d12 1 1 c1t0d0s3
  d1 -m d21 d11 1               /var
  d21 1 1 c1t1d0s1
  d11 1 1 c1t0d0s1
  d0 -m d20 d10 1               /
  d20 1 1 c1t1d0s0
  d10 1 1 c1t0d0s0
  

thanks in advance and any advice will be great