> I am trying to sweep then to backup without failure.

If you don't deliberately disable garbage collection, then I doubt
the sweep will do anything of use here.

> However it seems a mend is required before a backup,

Only if you have corruption. If you do have corruption, then yes you
need to mend, then backup, then restore. If the database is not
corrupt, then a mend is not necessary.

> What is the -g option?

The -g option tells gbak you don't want to perform garbage collection
during the backup process. If you are about to delete the source
database after you have backed up and restored somewhere else, then
you might as well not do this housekeeping. If your backup is just
part of your daily routine, then it might as well do the garbage
collection while it is going.

> I am using the Backup Service in IBOAdmin to do the backup
> and not a call directly to gbak.

I don't use IBO, but I assume it uses the same services API as gbak
so the same options will be available.

Adam