Tips and Pitfalls: iSCSI and iSLB

Common Commands

show iscsi initiator summary
show iscsi initiator detail
show iscsi session initiator initiator target target
iscsi save-initiator name name
show islb initiator
show islb session
show islb vrrp summary
show islb vrrp assignment

Key Points / Pitfalls

  • Incoming and outgoing CHAP passwords must be different
  • Iscsi import target fc does not apply to iSLB initiators
  • If IVR and iSLB features are enabled in the same fabric, you should have at least one switch in the
    fabric where both these features are enabled. Any zoning-related configuration and activation (for
    normal zones, IVR zones, or iSLB zones) must be performed on this switch. Otherwise, there may
    be traffic disruption in the fabric.
  • All iSCSI interfaces in a VRRP group that has load balancing enabled must have the same interface
    VSAN, authentication, proxy initiator mode, and forwarding mode.
  • If an Ethernet PortChannel is configured between the IPS module and an Ethernet switch, the load
    balancing policy on the Ethernet switch must be based on source/destination IP address only, not port
    numbers, for load balancing with VRRP to operate correctly.
  • A Gigabit Ethernet interface configured for iSLB can only be in one VRRP group because redirected
    sessions do not carry information about the VRRP IP address or group.
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6 Responses to Tips and Pitfalls: iSCSI and iSLB

  1. Caio Oliveira says:

    Feeny, one doubt:
    Is it necessary when using proxy-initiator that iscsi interfaces have different pwwns in different MDSs?
    (Example MDS1-iscsi2/1 and MDS2-iscsi2/1 with proxy-initiator mode having pwwn 11:11:11:11:11:11:11:11)?

    Or the right configuration should be
    MDS1-iscsi2/1 – pwwn 11:11:11:11:11:11:11:11
    MDS2-iscsi2/1 – pwwn 22:22:22:22:22:22:22:22

  2. Caio Oliveira says:

    I´m facing a problem like that: If you have iscsi1/1 on mds1 and iscsi1/1 on mds2 configured both as proxy-initiator and have VRRP configured between g1/1 on mds1 and g1/1 on mds (g1/1 is the VRRP primary on mds1). In that case, it´s not possible to set the pwwn of both iscsi proxy-initiator with the same pwwn?

    • brian says:

      proxy-initiators should each have their own pwwn’s, you should not be using the same pwwn’s even if you are doing VRRP. The only time you would have the same is if your doing a virtualization like SDV.

  3. Caio Oliveira says:

    Tks Feeny.
    Another doubt: In the lab exam, is possible to test iSCSI configurations? Is there a iSCSI initiator software to test?

    • brian says:

      I am not sure what I can and can’t say about what types of systems are in the lab, so I will have to not directly answer. My short answer is you don’t have to be worried about this, anything you do, you should be able to verify in some way, at least the important stuff.

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