Planning for multiple IP address for Ethernet connectivity

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Planning for multiple IP address involves creating a portset, assigning the IP address to portset, and mapping portset to host object or IP partnership. Portsets are groupings of logical addresses that are associated with the specific traffic types. The system supports both Fibre Channel and IP portsets for host attachment, IP portsets for backend storage connectivity, and IP replication traffic. The system supports a maximum of 72 portsets.

Each physical Ethernet Port can have maximum 64 IP addresses with each IP on unique portset. However, for each port IP address can be shared between multiple unique portsets for different functions. Each port can bind to only single IP address per portset for specific Ethernet functions like host attachment (iSCSI ), backend storage connectivity (iSCSI only), and IP replication. In most cases, host attach IP addresses can be separated by VLANs or subnets or a combination of both for multi-tenant scenarios. For cloud environments, each Ethernet port supports a maximum of two IP addresses and VLANs per port for multiple clients that share storage resources on the system.
Note: IBM® FlashSystem 7300 models do not support iSER-host attachment.
Table 1 lists limits for configuring IP addresses for host attachment, iSCSI storage virtualization, and IP replication. If you are using host bus adapters, see Table 2 for further limits.
Table 1. Limits for IP address in portsets
Limit Description
Maximum number of Portset objects 64 per system
Maximum number of IP address objects (includes shared IP address objects) 2048 per system
Maximum number of IP addresses objects per port 64 (either IPv4 or IPv6)
Maximum number of routable IP addresses objects per port 1 1 (either IPv4 or IPv6)
Maximum number of IP address objects per node 256 per node
Maximum number of IP addresses objects per node per portset

Host portsets - 4 per node per portset

Replication portsets - 1 per node per portset

Storage portset (Portset 3) - Limit to the number of Ethernet ports on the node
Maximum number of iSNS servers 1 IPv4 and 1 IPv6 - supported for portset0 IP addresses only
1 The routable IP addresses are used by IP replication function. However, if routable IP addresses are required for host attach and storage, each ethernet port can be assigned with 1 routable IP address with a gateway.
If you are using host bus adapters, the following limits apply to multiple IP addresses and VLANs:
Table 2. Limits for Host Bus Adapters
Type of HBA Limit
Emulex
  • Maximum of 3 unique VLANs per port
  • Maximum of 32 IP addresses per port1
Mellanox
For iSER2 connections:
  • Maximum of 31 VLANs per port
  • Maximum of 31 IP addresses per port with VLAN
  • Maximum of 64 IP addresses per port without VLAN
For iSCSI only connections:
  • Maximum of 64 VLANs per ports
  • Maximum of 64 IP addresses per ports
1 If a VLAN is not configured on these ports, the limit is still 32 IP addresses per port. You cannot add any more IP addresses or VLANs after this limit is reached.
2 If you are using iSER for clustering (node-to-node) connections, you need to lower the number of IP addresses per port based on the number that you are currently using for clustering.

Before creation of portsets and assigning them to IP address or host objects or IP partnerships, fulfill the various prerequisites for portsets and ownership groups.

Requirements for Ethernet portsets

In general, Ethernet portsets have the following requirements:
Ethernet Portsets
  • Portsets are system-wide objects where IP addresses from all nodes might be included in the portset for host, storage, and replication functions.
  • Each IP address in a portset must be configured on a separate Ethernet port.
  • Same ports can share IP addresses across different portsets that allow the same IP address to be used for host, storage, and remote-copy traffic. All shared IP addresses must use the same port and have the same VLAN, gateway, and prefix. When IP addresses are shared among multiple portsets, the system creates a logical copy of the IP address and its attributes, rather than a new IP address.
  • Portsets that are owned by different ownership groups can share an IP address.
  • A port can have 64 unique or shared IP addresses. All 64 IP addresses can be IPv4 or IPv6, or a mix of IPv4 and IPv6.
  • The Port Type field value defines if the portset is Ethernet. If you are using the command-line interface, specify ethernet in the port_type parameter of the mkportset command.
  • Each port can be configured with only one unique routable IP address (gateway specified). The routable IP can be shared among multiple portsets.
  • Portset 0 is a default portset that is automatically configured when the system is updated or created. Portset 0 is a host portset by default and cannot be deleted even if it is empty. Portset 0 serves as the default portset for any IP addresses and host objects that are configured without a portset specified. Portset 0 allows administrators to continue with an original configuration that does not require multi-tenancy. After an update, all configured Ethernet-based host objects are automatically mapped to portset 0.

Requirements for host portsets

In addition to portset 0, you can create more portsets for host traffic. These requirements are specific to host portsets:
  • Portsets can have a maximum of 4 IP addresses per node.
  • A single portset can either contain IPv4 or IPv6 or mix of IPv4 and IPv6 addresses.
  • For a host to log in to nodes on the system, the host must be mapped to a portset that contains at least one IP address from any of nodes on that system.

Requirements for replication portsets

You can create replication portsets for IP partnership. These requirements are specific to replication portsets:
  • Replication portset can have maximum of 1 IP address per node.
  • All IP addresses in replication portsets must be either IPv4 or IPv6 addresses. You cannot mix IP protocol versions on replication portsets.
  • Each IP partnership can be mapped to two portsets, one for each link between systems. For a partnership with a single link, a single portset can be defined in the portset1 field on the Create Partnership page in GUI. You can also use the -link1 attribute in the mkippartnership command for partnerships with a single link to specify one of the portsets. For a partnership with dual links, a second portset must be defined in the portset2 field in GUI. Use the -link2 attribute to specify the second portset for a dual link configuration.
  • Portsets replace the requirement for creating remote-copy groups for IP partnerships. During updates of the software, any IP addresses that are assigned to groups with an existing IP partnership are automatically moved to a corresponding portset. For example, if group 1 is defined on the system before the update then IP addresses from that remote-copy group are mapped to portset 1 after the update. Similarly, IP address in group 2 is mapped to portset 2.

For more information about IP partnership requirements, see IP partnership requirements.

Requirements for storage portsets

The system supports maximum of one portset of storage type, that is, portset 3. These requirements are specific to storage portsets:
  • The maximum number of IP addresses for a storage portset is equal to the number of Ethernet ports on the node.
  • A single portset can either contain IPv4 or IPv6 IP or mix of IPv4 and IPv6 addresses.
  • You cannot create the storage type portset.

Requirements of ownership groups for portsets

You can assign portsets to ownership groups to further restrict portset to a specific set of users:
  • Restricted users can create a portset and IP addresses and assign the hosts to portset.
  • Restricted users cannot view portsets that are assigned to a different ownership group.
  • Restricted users cannot own replication or storage type portset.