Re: RAID 1 or Hammer

["Gergo Szakal" <bastyaelvtars@xxxxxxxxx>]

"nntp.dragonflybsd.org" <mneumann@ntecs.de> wrote in message 
496b8121$0$881$415eb37d@crater_reader.dragonflybsd.org">news:496b8121$0$881$415eb37d@crater_reader.dragonflybsd.org...
> Hi,
>
> I'm curious if RAID 1 (mirroring) really helps to protect data loss. Of 
> course if a whole disk "dies", RAID 1 has the advantage that
> I have an identical copy. But what happens if only a sector of one disk
> contains bad data. How can the RAID controller decide which is the
> correct sector? Or would the disk detect such a case and return an error?

IMHO RAID provides redundancy and higher data availability while HAMMER 
mirroring
provides data safety by by backups. Having a non-0 RAID array is not equal 
to data
safety IMHO. Only backups can provide that.

Just my very own 0.02 though.