IBM DS8000 manual Server0

The DS Storage Manager GUI guides the user to use the same RAID types in an extent pool. As such, when an extent pool is defined, it must be assigned with the following attributes:

–Server affinity

–Extent type

–RAID type

The minimum number of extent pools is one; however, you would normally want at least two, one assigned to server 0 and the other assigned to server 1 so that both servers are active. In an environment where FB and CKD are to go onto the DS8000 storage server, you might want to define four extent pools, one FB pool for each server, and one CKD pool for each server, to balance the capacity between the two servers. Of course you could also define just one FB extent pool and assign it to one server, and define a CKD extent pool and assign it to the other server. Additional extent pools may be desirable to segregate ranks with different DDM types.

Ranks are organized in two rank groups:

–Rank group 0 is controlled by server 0.

–Rank group 1 is controlled by server 1.

Important: You should balance your capacity between the two servers for optimal performance.

Figure 5-6is an example of a mixed environment with CKD and FB extent pools.

Server0

Extent Pool CKD0

1113	1113	1113	1113
Cyl.	Cyl.	Cyl.	Cyl.
CKD	CKD	CKD	CKD

1113	1113	1113	1113
Cyl.	Cyl.	Cyl.	Cyl.
CKD	CKD	CKD	CKD

Extent Pool FBtest

1GB 1GB 1GB 1GB

FB FB FB FB

1GB	1GB	1GB	1GB
FB	FB	FB	FB

Extent Pool CKD1

1113	1113	1113	1113
Cyl.	Cyl.	Cyl.	Cyl.
CKD	CKD	CKD	CKD

Extent Pool FBprod

1GB	1GB	1GB	1GB
FB	FB	FB	FB

1GB	1GB	1GB	1GB
FB	FB	FB	FB

1GB	1GB	1GB	1GB
FB	FB	FB	FB

Server1

Figure 5-6 Extent pools

You can expand extent pools by adding more ranks to an extent pool.

90DS8000 Series: Concepts and Architecture