Hp XP P9500 Storage Manuel d'utilisateur télécharger pdf (Page 7)

The WLM manages workloads on MVS systems and has two operation modes to support dynamic

and static Parallel Access Volumes operations.

WLM in goal mode

The WLM must be in goal mode to support dynamic Parallel Access Volumes operations. The WLM

is in goal mode when the Dynamic alias management setting in the WLM Service Coefficient/Service

Definition Options dialog box is set to YES. While in goal mode, the WLM manages the system

to meet a performance goal.

WLM in compatibility mode

The WLM must be in compatibility mode to support static Parallel Access Volumes operations. The

WLM is in compatibility mode when the Dynamic alias management setting in the WLM Service

Coefficient/Service Definition Options dialog box is set to NO. While in compatibility mode, WLM

manages the system according to parameters in IPS and ICS (IEAIPSxx and IEAICSxx parmlib

members).

Hyper Parallel Access Volumes

The Hyper Parallel Access Volumes feature allows you to assign alias devices to one base device,

but have all other base devices in the same CU share these aliases.

When using the Hyper Parallel Access Volumes feature, the number of alias devices assigned to

each base device does not need to change, as is required when using Parallel Access Volumes in

dynamic mode. With the Hyper Parallel Access Volumes feature, a whole collection of alias devices

can be mapped to one single base device in a CU.

You can specify the PAV feature (Parallel Access Volumes or Hyper Parallel Access Volumes) to

use for each host computer. Therefore, an alias device may accept I/O requests issued through

Parallel Access Volumes or Hyper Parallel Access Volumes.

Flow of I/O requests using Parallel Access Volumes

Multiple alias devices are assigned to a base device in a CU to enable the base device to handle

multiple I/O requests.

In the following figure, three alias devices are each assigned to base devices 1, 2, and 3. As

illustrated with the arrows in the figure, I/O requests converge on base device 1 when a host

computer accesses the device using Parallel Access Volumes. Since alias devices A, B, and C were

assigned to base device 1 in advance of the operation, I/O requests are automatically issued to

these alias devices. Similarly, if a host computer accesses base devices 2 and 3, the I/O requests

are automatically issued to the alias devices assigned to those two base devices. Base device 4

is not able to process multiple I/O requests since no alias devices are assigned to the device.

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Hp XP P9500 Storage Manuel d'utilisateur Page 7