Re: Strange Behavior with Added Drives?

[John Jones <chianime@xxxxxxxxx>]

Parity space (RAID overhead) was reserved by the first 6 drives when the set
was originally built so the RAID controller didn't need to reserve space
from the 7th & 8th drive.

No big deal and there's no problem.

You could break the RAID set and rebuild it to spread the reserved space
over all 8 drives but frankly it's a lot of effort for virtually no payoff.

On Thu, Oct 27, 2011 at 4:43 PM, Bill <brobins3d@xxxxxxxxx> wrote:

> We've got a new 8202/720 that originally came with 6 drives that I
> formatted to Raid 6.  System's been up and running but not in production
> for over a month.  I decided to add another 2 to fill out the cabinet
> before the unit was placed into production.
>
> When the drives were to the system and then to the Protection Pool, they
> show up with a different capacity than the original 6:
>
>                 Size    %     I/O   Request   Read  Write   Read   Unit
>  Type      (M)  Used    Rqs  Size (K)    Rqs   Rqs     (K)
>     1  198C    93046  15.2     .0       .0      .0     .0     .0
>     2  198C    93046  15.2     .0       .0      .0     .0     .0
>     3  198C    93046  15.2     .0       .0      .0     .0     .0
>     4  198C    93046  15.2     .0       .0      .0     .0     .0
>     5  198C    93046  15.2     .0       .0      .0     .0     .0
>     6  198C    93046  15.2     .0       .0      .0     .0     .0
>     7  198C   139569  15.2     .0       .0      .0     .0     .0
>     8  198C   139569  15.2     .0       .0      .0     .0     .0
>
> Everything I've read so far just notes that Raid 6 effectively removes
> the capacity of 2 drives from the set, there's nothing that mentions
> behavior like the above with a quantity over 6.  Does the sizes reported
> above make sense?
>
> Bill
>
>
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