You can check the filesystem type by using fdisk on the external drive, usually
/dev/da0 under FreeBSD.
For an example see
http://www.daemonforums.org/showthre...5708#post36922
Usually external drives are formatted with DOS/FAT32 or NTFS.
The problem with FAT32 is the maximum file size of 4 GB. NTFS cannot be written to reliably on most BSDs.
Re: command to dump a fileystem
You forgot the '-a' option.
See
http://www.daemonforums.org/showthre...5708#post36923
If your drive is HFS+ and FreeBSD does not support reading/writing HFS+, FreeBSD cannot write the dump file to it.