To "hardware" RAID 5 or software RAID 5

[David G. Miller]

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

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