IBM DS8000 manual Sparing Example 2 RAID-10

Sparing Example 2 – RAID-10:

All same capacity, same RPM

	3x2 + 2S	4x2	4x2	3x2 + 2S
	Array	Array	Array	Array
DA	1	…		3
	2	…		4

•Assumes all devices same capacity & same RPM

•Minimum of 4 spares per DA pair

–2 spares per loop & 2 spares in each array group

–Additional RAID-10 arrays will be 4x2

–Any additional RAID-5 arrays will 7 + P

•All spares available to all arrays on DA pair

DA

Figure 9-10 Sparing example 2: RAID-10 - All same capacity, same RPM

In Figure 9-10,four RAID-10 arrays are installed in a DA pair. Two arrays need two spare disk drives (3x2+2S). One spare disk is in one loop and other spare disk is in the other loop in an array. The other two arrays don’t need spare disks (4x2).

If you add other arrays configured with the same capacity and RPM as in this DA pair, additional arrays don’t need spare disks (the arrays will be configured as RAID-5:7+P, RAID-10:4x2).

178DS8000 Series: Concepts and Architecture