Configurations for IBM Power Systems hosts running IBM i

Edit online

To achieve an efficient connection with your DS8000®, follow the configurations for IBM® i hosts that are running the IBM i operating system.

The following example shows output of the logical hardware resources of the hardware service manager that are associated with the IOP:

Opt Description                     Type-Model	  Status          Resource Name

Combined Function IOP               2843-001     Operational     CMB04
 Storage IOA                        280E-001     Operational     DC18
  Disk Unit                         2107-A82     Operational     DD143
  Disk Unit                         2107-A81     Operational     DD140
  Disk Unit                         2107-A81     Operational     DD101
The following example shows output of the logical hardware resources of the hardware service manager that are associated with the Smart IOA Fibre Channel adapter:

Opt Description                     Type-Model	  Status          Resource Name

Virtual IOP                         577F-001     Operational     CMB09
 Storage IOA                        577F-001     Operational     DC06
  Disk Unit                         2107-A04     Operational     DD017
  Disk Unit                         2107-A04     Operational     DD019
  Disk Unit                         2107-099     Operational     DD020
  Disk Unit                         2107-099     Operational     DD021
The following example shows output for the hardware service manager auxiliary storage hardware resource detail for the storage system:

Description........................:  Disk unit
Type-Model.........................:  2107-A04
Status.............................:  Operational
Serial number......................:  50-00413
Part number........................:  
Resource name......................:  DD017
licensed machine code .............:  FFFFFFFF
Level..............................:  0
PCI bus............................:  
  System bus.......................:  24
  System board.....................:  0
  System card......................:  0
Storage............................:  
  I/O adapter......................:   
  I/O bus..........................:  0
  Controller.......................:  1
  Device...........................:  1

You can define the storage system LUNs as either protected or unprotected. From a storage system, physical-configuration viewpoint all IBM i volumes are RAID-5, RAID-6, or RAID-10 volumes and are protected within the storage system. When you create IBM i volumes, you can create them as logically protected or unprotected, depending on the intended use of the LUNs in the IBM i configuration.

Table 1 shows the provisioned capacity for the protected and unprotected models. Logically unprotecting a storage LUN, allows the IBM i host to complete remote load source mirroring to that device. Because the load source is mirrored on an external LUN, the storage system can copy or transfer this load source as a disaster recovery backup. When you use the IBM i toolkit, an IBM i host in a remote location, which uses a copy of the original load source, can recover this load source and start running as if this recovery box were the original source host.

Table 1. Capacity and models of volumes for IBM i hosts that are running IBM i operating system
Size Type Protected model Unprotected model
8.0 GiB 2107 A01 A81
16.3 GiB 2107 A02 A82
32.7 GiB 2107 A05 A85
65.7 GiB 2107 A04 A84
131.4 GiB 2107 A06 A86
262.9 GiB 2107 A07 A87
1 GiB to 2000 GiB 2107 099 050

IBM i supports multipath attachment through Fibre Channel as part of the base IBM i operating system. Obtain a list of supported host adapters on the IBM System Storage® Interoperation Center (SSIC) website

Notes:
  • A number of Fibre Channel and FCoE CNA adapters are not natively supported by IBM i. However, many of these adapters are supported when used in a Virtual I/O Server (VIOS) partition. Refer to the IBM System Storage Interoperation Center (SSIC) website for a list of these adapters.
  • DS8000 LUNs can be assigned to the IBM i partition as either natively attached (non-VIOS) or vFC (NPIV).

Multipath is important for the IBM i partitions because it provides greater resilience to storage area network (SAN) failures, which can be critical to IBM i due to the single-level storage architecture. Additionally, having multiple paths to a logical volume can improve the I/O performance of the partition.

Up to eight connections from multiple I/O adapters in an IBM i partition can be defined to a single logical volume in the DS8000. Each connection for a multipath disk unit functions independently. Several connections provide redundancy by allowing disk storage to be used even if a single path fails.

New paths are automatically detected, configured by the system, and immediately used. If a disk is initially set up as a single path and a second path is added, the resource name of the disk unit is modified from DDxxx to DMPxxx. This modification reflects that it now has more than one path to the disk unit. No user changes are required on the IBM i host to use the new path. Multipath connections can be directly connected or connected through a fabric. For more information, see the section on displaying disk multipath information and status.

To activate multipathing on the IBM i host, use the DS8000 Storage Management GUI.

With IBM i operating system, path information is available for the disk unit hardware configuration from the IBM i Navigator.

To improve the availability of Fibre Channel disks, use the following configuration guidelines to help you achieve optimum IBM i I/O performance:

  • Use the Disk Magic Analysis tool to calculate the smallest LUN size possible to allow more IBM i-active I/O, without affecting device response times.
  • Use High-Performance Flash drives or RAID-10 LUNs for performance-critical applications.