To "hardware" RAID 5 or software RAID 5

Robin Laing Robin.Laing at drdc-rddc.gc.ca
Thu Dec 7 16:46:54 UTC 2006


On Wed, 2006-12-06 at 15:00 -0700, David G. Miller wrote:
> Robin Laing <Robin.Laing at drdc-rddc.gc.ca> wrote:
> 
> > On Mon, 2006-12-04 at 13:28 -0800, Gordon Messmer wrote:
> >> > Robin Laing wrote:
> >>     
> >>> > > On Sun, 2006-12-03 at 12:13 +0800, Hadders wrote:
> >>>       
> >>>> > >> RAID 6 - less used, but like 5, but handles more than a single disk failure.
> >>>>         
> >>> > > 
> >>> > > Thanks for this information.  I will have to look closer at RAID 6 for
> >>> > > my new file server.
> >>>       
> >> > 
> >> > Naturally, in order to provide the additional redunancy, you sacrifice 
> >> > more disk space.  In a RAID5 set, the parity is stored on the equivalent 
> >> > of the volume of one disk.  Your available space is N-1, where N is the 
> >> > size of the smallest disk used.  In RAID6, the available space is N-2. 
> >> > The additional redundancy is good if you have a large set of disks, but 
> >> > if you've got just three, it's probably overkill.  RAID5 is the best 
> >> > solution for a 3 disk set.
> >> > 
> >>     
> >
> > I was looking at 5 disks minimum in the new server.  The better recovery
> > is what I am concerned with.  Just in case.  Backing up a TByte of data
> > is a pain.
> RAID does not protect against fat fingers.  One wrong rm can still mean 
> you need a back-up.
> 
> Cheers,
> Dave
> 
> -- 
> Politics, n. Strife of interests masquerading as a contest of principles.
> -- Ambrose Bierce
> 

No kidding.  Most of the files will be from media in the first place so
the biggest issue would be re-installing it on the server.

Now I will backup but to external HD's as this is now a low cost
approach.




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