to use the shadow as backup

# shut down the database
gfix -shut -force 0 database.gdb
# rename the shadow file in order to gfix don't locate when you try
to kill
the shadow
mv database.shd database.shd.renamed
# kill unavaiable shadows (remove the reference to the shadow from the
master database, without erasing because you've renamed it)
gfix -kill database.gdb
# brings the database to live, to your happy users
gfil -online database.gdb

The downtime is very small this way

Hope this helps, and sorry my Tarzan english
Geraldo Lopes de Souza