Backup advice

[Jason Lixfeld]

So I feel a need to start backing up my servers.  To that end, I've  
decided that it's easier for me to grab an external USB drive instead  
of a tape.  It would seem dump/restore are the tools of choice.  My  
backup strategy is pretty much "I don't want to be screwed if my RAID  
goes away".  That said I have a few questions along those lines:

- Most articles I've read suggest a full backup, followed by  
incremental backups.  Is there any real reason to adopt that format  
for a backup strategy like mine, or is it reasonable to just do a  
dump 0 nightly?  I think the only reason to do just one full backup  
per 'cycle' would be to preserve system resources, as I'm sure it's  
fairly taxing on the system during dump 0 times.

- Can dump incrementally update an existing dump, or is the idea that  
a dump is a closed file and nothing except restore should ever touch it?

- How much does running a backup through gzip actually save?  Is  
taxing the system to compress the dump and the extra time it takes  
actually worth it, assuming I have enough space on my backup drive to  
support a dump 0 or two?

- Other folks dumping to a hard drive at night?  Care to share any of  
your experiences/rationale?

Thanks in advance.