# mount /dev/fslv00 /test
mount: 0506-322 Cannot determine log device to use for /dev/fslv00 (/test).
Just create another logical volume in datavg vg with a size of one (1) PP.
# mklv -t jfs2log -y <yournewloglv>datavg vg 1 # logform /dev/<yournewloglv>
Any filesystem that is created in datavg vg after this step will automatically use it.
Any filesystem that has been there before can be made using your new loglv with
# chfs -a log=<yournewloglv> <filesystemname>
If you create your loglv make sure to place it on the edge (-e) of your disk.
These are rather basic tasks. If you feel uncomfortable accomplishing them on the commandline you might want to use SMIT. Works fine.
Edit /etc/filesystems to add /dev/fslv00 as a new filesystem:
/test: dev = /dev/fslv00 vfs = jfs log = /dev/"jfs_log_name" mount = true options = rw account = false
Run fsck against /dev/fslv00 , and try mounting it again.