>
> If you don't need high performance, and you don't want to buy a spare card
> in case the 3ware card dies, you might want to consider raidframe. Otherwise,
> your just adding a new single point of failure into your systems.
>
and this always is true - from raid(4):


WARNINGS
      Certain RAID levels (1, 4, 5, 6, and others) can protect against some
      data loss due to component failure.  However the loss of two 
components
      of a RAID 4 or 5 system, or the loss of a single component of a RAID 
0
      system, will result in the entire file systems on that RAID device 
being
      lost.  RAID is NOT a substitute for good backup practices.



spending little bit less money for backup system, or very little money for 
somehow smarter backup system is much better solution.
DVD+RW drive+dump(8) is usually enough if differential backups are used 
and most unneeded or regenerable data is flagged with chflags nodump.

it works excellent for me, but verification is absolutely necessary with 
DVD+RW!!! even with expensive discs you are never sure!

other cheap backup media is USB 2.0 connected hard drive.

but ONLY backup is really good if backup media is physically disconnected 
after usage - or it is almost no protection at all.


disc failures are not more probable than software failure, other hardware 
failure (transmitting bad data through bus), security compromise etc.

only true backup with media disconnected after usage means some 
real security, while all RAIDs are in most (not all) cases pure waste of 
money.