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Pure Storage KnowledgeCenter Errata

Preventive Service Planning


This erratum should be used by anyone using the IBM System Storage SAN Volume Controller Software to configure these systems with the Pure Storage Flash Arrays.


Who should use this guide

This erratum should be used by anyone using the IBM System Storage SAN Volume Controller Software to configure these systems with the Pure Storage Flash Arrays.

You should review the errata contained within this guide and note the details with respect to the suitable SVC infocenter information and Best Practices from the Redbooks.

Note; SAN Volume Controller, SVC, also denotes suitable IBM Storwize controllers.

Configuring the Pure Storage FlashArray FA-400, FA-//MR1/R2, FA-//XR1 series

Configuring the FlashArray.

This portion of the document covers the necessary configuration for using a Pure Storage FlashArray with an IBM SAN Volume Controller cluster.

Support models of FlashArray

Please see the IBM System Storage Interoperation Center web site at for full and up-to-date details.

Initial Support firmware levels of FlashArray

Purity Version: 3.2.x
SVC Version

Concurrent maintenance on FlashArray

Concurrent Firmware upgrades are supported as per FlashArray procedures.

FlashArray interface

This is the Pure Storage Storage Management Utility GUI.
Users configure a FlashArray via a web browser.

There is also a CLI accessed via ssh sessions.
SNMP and Remote Assist can be configured.

Explanations will assume use by the GUI.
Setup is largely intuitive, with minimal settings or configuration.
Create Host, Create Volume, Connect Host.

Logical units and target ports on FlashArray


The FlashArray supports LUN sizes from 1MB to 4PB.
A Volume is referenced by the Volume name.

FlashArray can export 5000 LUNs.
However only 256, if configuring SVC as single Host.
From Pure OS f/w 4.8.x this limit is 500.
See relevant Pure documentation.
SVC documented limits will be in;
Vx.x Configuration Limits and Restrictions for IBM System Storage SAN Volume Controller
Greater than 2TB LUNs are supported by SVC.

SVC will detect the controller when zoned without Luns being provisioned.

The Lun number can be edited, but Lun 0 is “invalid” and not used.

All controller ports present the same Luns.


FlashArray will identify exported Logical Units through
SCSI Identification Descriptor type 3.
The 64-bit, NAA IEEE Registered Extended Identifier (NAA=6
for the Logical Unit is in the form;
The FlashArray IEEE Company ID is; 24a937 (PURE Storage),
the rest is a vendor specific ID.

# lsmdisk 9
id 9
name mdisk8
status online
mode managed
mdisk_grp_id 1
mdisk_grp_name mdiskgrp0
capacity 100.0GB
quorum_index 2
block_size 512
controller_name controller0
ctrl_type 4
ctrl_WWNN 524A93744B570E03
controller_id 0
path_count 16
max_path_count 16
ctrl_LUN_# 000000000000000A
UID 624a93701036178b84e160770001101a00000000000000000000000000000000
active_WWPN many
fast_write_state empty
tier enterprise
fabric_type fc
easy_tier_load high
encrypt no

Configure Pure Storage including Logical Drives and Hosts.

Settings are in general default unless specified.

The Array will be configured as a large virtualised, thin provision and de-dupped storage pool. If over-allocating the storage capacity, care should be taken to monitor the systems remaining capacity to avoid taking related SVC mdiskgroups offline.

The underlying storage is not visible but has 7+2P “RAID-3D” structure.

Zone SVC to the storage first, and check SVC can see all the expected controller ports as controllers. [ svcinfo detectmdisk, svcinfo lscontroller ]

Creating an SVC Host;
SVC can be either a Host or if preferred a Host Group, there is no difference.
From main page on GUI go to Storage, click Hosts then select “+”
In the Dialogue box enter a suitable name for the SVC cluster,
the new host will be highlighted, then select “Host Ports” along the bar.
Click the right “gear wheel” and select “Configure Fibre Channel WWNs”
The SVC ports should all then be visible and selectable.
Add them all to the Host.

Creating Volumes;
From main page on GUI go to Storage, click Volumes then select “+”
Single or multiple volumes can be provisioned. Only selectable option is size.
There is a “gear wheel” selection menu on the right for other volume tasks.

Connecting SVC as a Host;
From main page on GUI go to Storage, click Hosts and select the new SVC Host.
Select “Connected Volumes” on the bar.
Go to the “gear wheel” on the right and select “Connect Volumes”
Select the volumes you wish to present to SVC.

Check on SVC that all is presented as expected and any errors corrected.
[ svctask detectmdisk, svcinfo lsdiscoverystatus]

id controller_name ctrl_s/n vendor_id product_id_low product_id_high
0 controller0 PURE FlashArr ay
1 controller1 PURE FlashArr ay
2 controller2 PURE FlashArr ay
3 controller3 PURE FlashArr ay
4 controller4 PURE FlashArr ay
5 controller5 PURE FlashArr ay
6 controller6 PURE FlashArr ay
7 controller7 PURE FlashArr ay

To Modify, Resize, or destroy a Volume/LUN,.

The Volume must be removed from any SVC mdiskgroup and be in an “unmanaged” state before doing any modifications on the controller.

*** Note: Make sure the SVC mdisk is unmanaged (removed from any mdiskgroup) on the SVC Cluster before deleting the Volume on the Pure Storage FlashArray storage system.

*** Note: Do not use volume expansion on LUNs that are in use by a SAN Volume Controller cluster. For this to be recognised by SVC the mdisk must
be first made unmanaged by migrating or deleting from the MDiskGroup.

LUN Presentation

LUNs are exported through all the FlashArrays available FC ports. .

Special LUNs

There are no special considerations to a Logical Unit numbering. LUN 0 is not presented or configurable.

Target Ports

A FlashArray storage system can have a total of 8 - 20 FC ports.
Note current SVC limit of 16.
Each WWNN will have an associated controller with 1x WWPN

lscontroller 0
id 0
controller_name controller0
WWNN 524A93744B570E03
mdisk_link_count 16
max_mdisk_link_count 17
degraded no
vendor_id PURE
product_id_low FlashArr
product_id_high ay
product_revision 100
allow_quorum yes
fabric_type fc
WWPN 524A93744B570E03
path_count 32
max_path_count 32

FlashArray WWNN and WWPN settings look like this:


5 - IEEE 803.2 extended 48-bit ID NAA format,
24A937 - IEEE unique VSID of OEM for Pure Storage.
SSSSSSS - unique vendor-supplied serial number for the device.
PP - vendor specific code used to identify specific ports and controller

WWPN 524A93744B570E03
WWPN 524A93744B570E13
WWPN 524A93744B570E00
WWPN 524A93744B570E11
WWPN 524A93744B570E02
WWPN 524A93744B570E12
WWPN 524A93744B570E01
WWPN 524A93744B570E10

LU access model

All controllers are Active/Active. In all conditions, it is recommended to cross connect the ports across FC switches to avoid an outage from controller failure.
All FlashArray controllers are equal in priority so there is no benefit to using an exclusive set for a specific LU.

LU preferred access port

There are no preferred access ports on the FlashArray as all ports are Active/Active across all controllers.

Detecting Ownership

Detecting Ownership does not apply to FlashArray.

Switch zoning limitations for FlashArray

There are no zoning limitations for FlashArray.
The FlashArray system presents itself to an SAN Volume Controller cluster as a separate controller for each WWPN. For example, if one of these storage systems has 4 ports zoned to the SAN Volume Controller, it appears as 4 controllers each with a single WWPN. A given logical unit (LU) is mapped to the SAN Volume Controller through all controller ports zoned to the SAN Volume Controller using the same logical unit number (LUN).

Fabric zoning

Each Fabric zone to all the SVC backend ports should contain at least one FlashArray storage system port from each controller for robustness,.

Example switch port of controller (name server)
N 030600; 3;52:4a:93:74:4b:57:0e:01;52:4a:93:74:4b:57:0e:01; na
FC4s: FCP [PURE FlashArray 100 ]
NodeSymb: [43] "QLE2562 FW:v7.02.00 DVR:v8.06.00.12-k-debug"
Fabric Port Name: 20:06:50:eb:1a:04:dd:bb
Permanent Port Name: 52:4a:93:74:4b:57:0e:01
Port Index: 6
Share Area: No
Device Shared in Other AD: No
Redirect: No
Partial: No

Target port sharing

The FlashArray storage system does not support LUN masking.

Host splitting

This can be done if the Multipathing Drivers are compatible.

Controller splitting

The controller may be shared with other hosts, provided svc has sole access to the LUNs presented to it as mdisks.

Configuration settings for FlashArray storage system

There are little if no settings configurable on the FlashArray, it is designed for
simple and intuitive configuration.

Quorum disks on FlashArray

The SAN Volume Controller cluster will select disks that are presented by the FlashArray storage system as quorum disks. To maintain availability for the cluster, ideally each quorum disk should reside on a separate disk subsystem.

Clearing SCSI reservations and registrations

This option is not available on the browser or cli.
Note; this should never be done, LUNs must be exclusive to SVC.

Copy functions for FlashArray storage system

The FlashArray replication and snapshot features are not supported under SVC.
Configuration Suggestions

Real-time compression and thin provisioning are built into Pure and cannot be disabled, so the option is available to use these functions without SVC. For thin provisioning care must then be taken to monitor the available storage capacity on the controller if over-allocating.

Consider creating Pure Storage mdisks in groups of 4 to allow extents to be equally distributed for optimum CPU processing.

Pure Storage mdiskgrps can be used in an EasyTier configuration but must be classed as a Tier 0 device, for SSD's.

The suggested optimum Pure Storage LUN size for presentation to an SVC is 2TB

Refer to the IBM svc infocenter and Redbooks for best practises.

Document information

More support for: SAN Volume Controller

Version: 7.4

Operating system(s): Platform Independent

Reference #: S1005055

Modified date: 26 February 2018