vxassist is used to grow volume and filesystem when vxresize should have been used. 

1. Check what size we put for filesystem size here -

# vxprint -qhtg dgname
v  testvol      -            ENABLED  ACTIVE   1044480  SELECT    testvol-01 fsgen
pl testvol-01   testvol      ENABLED  ACTIVE   1044480  STRIPE    3/128    RW                             <<  volume Size = 1044480 sectors
sd d1-06        testvol-01   d1       716800   341376   0/0       hds9500-alua0_210 ENA
sd d1-04        testvol-01   d1       1262976  6784     0/341376  hds9500-alua0_210 ENA
sd d3-06        testvol-01   d3       716800   341376   1/0       hds9500-alua0_217 ENA
 

2.    Check if the server is  primary for the filesystem with the following command below -

# fsclustadm -v showprimary

3. Login to primary server and then execute

# /usr/lib/fs/vxfs/fsadm -F vxfs -b 1044480 /tmnt

UX:vxfs fsadm: INFO: V-3-25942: /dev/vx/rdsk/posdb_dg/testvol size increased from 1024000 sectors to 1044480 sectors

4. Check the filesystem size

#  df -kl /tmnt
Filesystem                                          kbytes    used   avail capacity  Mounted on
/dev/vx/dsk/posdb_dg/testvol         522240  442348   74928    86%    /tmnt

where filesystem size = 522240kbytes
            volume size = 1044480/2 = 522240