By: Sam Matzek, PowerVC Image Management and Li Jun Zhu, PowerVC for IBM i

 

Before you use DS8870 storage with PowerVC to manage IBM i virtual machines, make sure that you understand the unique IBM i storage considerations.

Most configuration tasks to configure IBM i virtual machines with DS8870 storage are the same across all types of virtual machines. For example, just like other virtual machines, 512-byte sector volumes can be assigned to an IBM i virtual machine via vSCSI connectivity.

However, for an IBM i virtual machine connected to a DS8870 via NPIV, 520-byte sector volumes are required. This leads to special considerations when using PowerVC to manage an IBM i virtual machine with NPIV attached DS8870 storage.

DS8870 supports a variety of 520-byte sector volumes for IBM i usage:

 

Table 1. Capacity and models of 520-byte sector volumes for IBM i.

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

Variable

2107

099

050

* 1 GiB = 230 bytes.  1 GB = 109 bytes.  See https://en.wikipedia.org/wiki/Gibibyte

 

Notes: All of the Axx values imply a preset volume capacity, which is a fixed size. The protected and unprotected models 099 and 050 values do not imply a volume capacity and you can specify the capacity when using these values.

 

Considerations for using DS8870 storage

Be aware of the following considerations when using DS8870 storage with IBM i virtual machines managed by PowerVC:

  • To utilize NPIV connectivity for an IBM i VM, you must create storage templates for 520-byte sector volumes manually. The default storage template for DS8870 is created automatically when the DS8870 storage is imported into PowerVC. However, it only provides the capability to use 512-byte sector volumes. See the “Storage template setting considerations” section below for details.
  • To determine the model type for existing volumes that are managed by PowerVC either as part of an existing VM management or standalone volume management, refer to the “Data Type” field on the volume details page:

     
  • Before capturing an imported IBM i VM, you must set the compatible storage template as the default template. PowerVC can manage an existing IBM i VM with 520-byte sector volumes. However, PowerVC doesn’t create or set the storage template for existing volumes that are managed. For example, if you want to capture an imported IBM i VM whose load source is an A05 volume, you must set the storage template that has A05 capability as the default template. Otherwise, the capture will fail with this error: “establish Copy Services operation failure: incompatible volumes”.  To set the storage template as the default,  select the appropriate checkbox when editing the storage template details:

     

  • When capturing a deployed IBM i VM that has different types of volumes, ensure that it has a valid combination of volumes, as described in Table 2 below.  For example, if the VM has a 512 boot volume type and a 520 data volume type, the boot volume must be connected by vSCSI and the data volume must use NPIV. If the VM does not have a valid combination of volumes, it will not be deployable. 

To deploy an IBM i VM by using an imported image that is backed by 520-byte sector volumes, you must select the compatible storage template on the deploy page:

  • When creating a 520-byte sector volume, you must use a storage template that specifies your desired DS8870 IBM i model. 
  • An IBM i VM requires NPIV connectivity for a 520-byte sector volume attachment. A 520-byte sector IBM i volume with vSCSI connectivity is not supported.
  • An IBM i VM requires vSCSI connectivity for a 512-byte sector volume attachment.  A 512-byte sector IBM i volume with NPIV connectivity is not supported.If you deploy an IBM i image, you must select the correct storage connectivity group for successful deployment of VMs.  Volumes with 512 byte sector sizes may only be attached using vSCSI.  This includes both DS8870 volumes and VIOS SSP volumes.  Volumes with 520 byte sector sizes may only be attached using NPIV.
  • Storage template considerations
    • Advanced settings to create 099 / 050 storage templates: The PowerVC user interface enables you to create a storage template for 099 / 050 volumes. When you register a DS8870 on PowerVC, a default storage template is created for that provider. However, it only provides the capability for 512-byte sector volumes. Create a new storage template by following these steps:
      1. Go to Configuration > Storage Templates > Create. For Select a Storage Provider, select the DS8870 storage.
      2. Choose your storage pool.
      3. Specify the template name.
      4. Click Advanced Settings and choose the sector type.
      5. Optionally make this your default storage template for this storage provider.
    • Use a REST API to create an Axx storage template: Currently, the PowerVC user interface doesn’t support creating a storage template for an Axx volume.  However, you can create one by using the POST /v2/​{tenant_id}​/types REST API. Here is an example of the API request body:

{ “volume_type”:
{{ “extra_specs”:[
{“capabilities:volume_backend_name”: “The value of volume_backend_name in /etc/cinder/volume-*.conf“,
“drivers:display_name”: “User_defined_name“,
“drivers:os400”: “A05”,
“drivers:storage_pool”: “Pool_name“,
“drivers:thin_provision”: “True”}
],
“is_public”: “true”,
“name”: “ User_defined_name “}}}
 

 

With proper setup, PowerVC makes it simple to use DS8870 storage devices with IBM i virtual machines.  This simplicity is enabled by creating default templates that match your IBM i storage requirements for the DS8870.

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