RAID-DP

RAID-DP (Double Parity)

Raid DP is a Double Parity disk and this implementation that prevents data loss when two disk fail.

In Raid DP minimum 3 disks required to create one aggregate.

It will support multi disk failure.

In NetApp raid DP is default raid group.        

Example:

filer1> aggr create -r 5 aggr1 10

In this command "aggr create -r 5 aggr1 10"
aggr1 will randomly take 10 disk from spare disk and -r 5 which means each raid group should have 5 disks. 

So obviously here two raid group will create and each raid group should have 5 disks.

d1  d2  d3  P(d4)  DP (d5) => rg0 

d6  d7  d8   P(d 9)  DP (d10) => rg1

Note: 

d1 - d10 which means disk name

P for parity disk

DP for second parity disk

rg0 and rg1 are raid group 0 and 1

NetApp Raid

RAID-Redundant Array Of Independent Disks

In all the Raid in NetApp having minimum data disk and minimum parity disk
Disk Types

Data      : Holds data stored within the RAID group

Spare    : Does not hold usable data but is available to be added to a RAID group in an aggregate,

                also known as a hot spare

Parity    : Store data reconstruction information within the RAID group

dParity  : Stores double-parity information within the RAID group, if RAID-DP is enabled

These are type of disks in filler

DISK TYPE	RAID-DP	RAID4
ATA/BSAS/SATA                        Maximum	16	7
FC/SAS                         Maximum	28	14
ATA/BSAS/SATA                             Default	14	4
FC/SAS                          Default	16	7
ATA/BSAS/SATA                         Minimum	3	2
FC/SAS                       Minimum	3	2

In Netapp two raid supported

1. Raid4
2. Raid DP

In NetApp default  raid type is Raid Dp.




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