Datasheet
49
As of the publication date, only the following software or firmware is supported for IBM i directly
attached to DS5100 and DS5300 systems. This support is also reflected in “IBM i using open
storage supported configurations” section.
IBM i 6.1 with LIC 6.1.1 or higher
Controller firmware 07.60.28.00 or higher
DS Storage Manager 10.60.x5.17 or higher
IBM i Host Attachment Kit, FC #7735 (required)
Storage Partitioning (strongly recommended)
10.3 Best practices, limitations and performance
As with other storage subsystems, it recommended to create LUNs for IBM i production
workloads on FC drive RAID arrays only in order to meet the performance requirements of the
application. While SATA drives are supported for direct attachment to IBM i, they are best suited
for test, development and archival of IBM i workloads. Mixing FC and SATA drives within an
enclosure is supported along with solid-state drives (SSDs). Hardware encryption of the data on
the physical drives within the storage subsystem is supported.
All LUNs mapped directly to IBM i must be protected. Therefore, the supported RAID levels for
IBM i direct attachment are 1, 5 and 6. LUNs report as protected in IBM i; therefore, IBM i
mirroring is not possible. The reliability of the solution is based on the RAID protection within the
storage subsystem and on using multiple paths. The maximum LUN size for IBM i in this
environment is up to but not including 2TB (remember the load source minimum and maximum
sizes). The maximum number of LUNs per FC adapter port is 64. Dynamic volume (LUN)
expansion is not supported for IBM i. After LUNs have been mapped to IBM i, at most 300 from
the same subsystem can be added to an ASP with a single operation. More than 300 LUNs can
be added to an ASP in general, but they require multiple add operations.
There are no special requirements for the load source LUN, except of course sufficient size to
qualify as a load source for IBM i 6.1/I 7.1. The load source does not need to be the very first
LUN mapped to IBM i. When performing an Initial Program Load (IPL), an active path to the load
source LUN is required. Path failover is not possible during IPL; however, as soon as the IPL is
complete, failover functionality resumes.
As with other host types, each port on a FC adapter in IBM i should be zoned separately to
controller A or controller B on the storage subsystem. Furthermore, it is strongly recommended
to use Storage Partitioning when directly connecting to IBM i. Storage Partitioning is a premium
feature on the DS5100 and DS5300 which allows a set of LUNs to be associated only with
specified hosts and host ports. Storage Partitioning allows the creation of multiple host groups;
only the hosts within a particular host group are allowed access to a group of LUNs. Without that
premium feature, all hosts reside in the default host group, which allows IBM i to access LUNs
mapped to other hosts. The recommended approach is to use Storage Partitioning and create a
host group for each IBM i LPAR using the storage subsystem, placing the hosts associated with
that LPAR in the host group. Hosts representing different IBM i LPARs should not be placed in
the same host group, as IBM i does not support shared simultaneous access to the same LUNs
from multiple LPARs.
Note that migrating from IBM i using DS5100 or DS5300 storage system through VIOS to IBM i
using the same subsystem directly requires data migration, typically by save and restore. There
is no option to reassign the LUNs from a VIOS host to an IBM i host or to use IBM Tivoli®
Storage FlashCopy® Manager or VolumeCopy due to sector size differences..
Performance for IBM i directly attached to DS5100 and DS5300 system is very similar to that of
the same adapter and storage configuration attached through VIOS. Direct attachment
performance will not be significantly better than that of VIOS attachment for IBM i. Performance