I didn't think RAID 5 or RAID 6 kept all parity data on any one particular disk. I thought it was spread across all the disks. In the case of RAID 6 I thought that the parity was stored on different disks each time but never both on the same disk.
In any case, I think you both may be right. They are using a different parity algorithm for the second parity to be able to recover from a multiple disk failure which would cause the loss of multiple bits of the data. My bad on that one.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Luke -Jr Sent: Wednesday, June 06, 2007 12:39 PM To: [email protected] Subject: Re: SATA PT2
On Wednesday 06 June 2007 09:47, Phil Thayer wrote:
As for figuring out the second parity calculation on RAID
6, what the
manufacturers are realizing is that they don't necessarily
have to have
a different parity algorithm to calculate the second parity. Simply putting the same XOR parity data on two separate disks will
provide the
same RAID 6 functionality as having a second parity calculation with lower overhead on controllers. The old KISS methodology is
coming back
into play. I think you will see more and more of the manufacturers going this route.
That only works if one of the dead disks is a parity disk... _______________________________________________ Kclug mailing list [email protected] http://kclug.org/mailman/listinfo/kclug