I/O enclosures and host adapters (FC, FICON, zHyperLink)

You’ll read the ports of the lab DS8A50, find which host is logged in where and check the cabling against IBM’s rule. Two hosts are already logged in to the lab system, each with two HBA ports.

Practice shell note: the practice shell is our teaching tool, not IBM software. Real DS CLI output is similar but not identical, and the extra columns of lsioport -l and the location codes are ours. Lines starting with SIM are practice shell messages, and simctl commands exist only in the shell.

1Start clean

Start the shell with python ds8sim.py, log in and reset.

Run this:

simctl reset

You should see this:

SIM0100I simctl: factory state restored (users and passwords kept; use simctl reset -all to reset them too).

✅ Checkpoint: You are at the dscli> prompt.

2List the host adapters

Run this:

lshacard

You should see this:

Date/Time: 24 October 2026 11:11:13 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
ID                           I/O enclosure      Frame State  Type  Speed   Fibre Channel ports Encryption capable Location code         S/N
==================================================================================================================================================
IBM.1400-1B1-78SV0/R-1-P1-C1 IBM.1400-1B1-78SV0 1     Online FC-LW 32 Gb/s 4                   yes                U1400.1B1.78SV0-P1-C1 YH10SV0001
IBM.1400-1B2-78SV0/R-1-P1-C3 IBM.1400-1B2-78SV0 1     Online FC-SW 32 Gb/s 4                   yes                U1400.1B2.78SV0-P1-C3 YH10SV0003
IBM.1400-1B2-78SV0/R-1-P1-C4 IBM.1400-1B2-78SV0 1     Online FC-SW 32 Gb/s 4                   yes                U1400.1B2.78SV0-P1-C4 YH10SV0004
IBM.1400-1B3-78SV0/R-1-P1-C5 IBM.1400-1B3-78SV0 1     Online FC-SW 32 Gb/s 4                   yes                U1400.1B3.78SV0-P1-C5 YH10SV0005

There are four adapters: one long-wave card in 1B1, two short-wave cards in 1B2 and one in 1B3. You can already smell a design problem, since 1B2 has two adapters while 1B4 has none, which breaks IBM’s “one per enclosure first” rule.

✅ Checkpoint: You can name the enclosure of each of the four adapters.

3List the ports with their location

Run this:

lsioport -l

You should see this:

Date/Time: 24 October 2026 11:11:13 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
ID    WWPN             State                     Type             topo     portgrp Speed   Frame I/O Enclosure HA Card Security
===============================================================================================================================
I0010 50050763030130DD Offline                   Fibre Channel-LW -        0       32 Gb/s 1     1B1           C1      Disabled
I0011 50050763030170DD Offline                   Fibre Channel-LW -        0       32 Gb/s 1     1B1           C1      Disabled
I0012 500507630301B0DD Offline                   Fibre Channel-LW -        0       32 Gb/s 1     1B1           C1      Disabled
I0013 500507630301F0DD Offline                   Fibre Channel-LW -        0       32 Gb/s 1     1B1           C1      Disabled
I0030 50050763030330DD Communication established Fibre Channel-SW SCSI-FCP 0       32 Gb/s 1     1B2           C3      Disabled
I0031 50050763030370DD Offline                   Fibre Channel-SW -        0       32 Gb/s 1     1B2           C3      Disabled
I0032 500507630303B0DD Communication established Fibre Channel-SW SCSI-FCP 0       32 Gb/s 1     1B2           C3      Disabled
I0033 500507630303F0DD No light detected         Fibre Channel-SW SCSI-FCP 0       32 Gb/s 1     1B2           C3      Disabled
I0040 50050763030430DD Offline                   Fibre Channel-SW -        0       32 Gb/s 1     1B2           C4      Disabled
I0041 50050763030470DD Communication established Fibre Channel-SW FICON    0       32 Gb/s 1     1B2           C4      Disabled
I0042 500507630304B0DD Communication established Fibre Channel-SW SCSI-FCP 0       32 Gb/s 1     1B2           C4      Disabled
I0043 500507630304F0DD No light detected         Fibre Channel-SW SCSI-FCP 0       32 Gb/s 1     1B2           C4      Disabled
I0050 50050763030530DD Offline                   Fibre Channel-SW -        0       32 Gb/s 1     1B3           C5      Disabled
I0051 50050763030570DD Offline                   Fibre Channel-SW -        0       32 Gb/s 1     1B3           C5      Disabled
I0052 500507630305B0DD Communication established Fibre Channel-SW SCSI-FCP 0       32 Gb/s 1     1B3           C5      Disabled
I0053 500507630305F0DD Offline                   Fibre Channel-SW -        0       32 Gb/s 1     1B3           C5      Disabled

Read three columns together: topo says who may log in (SCSI-FCP or FICON), State says whether the cable is live, and I/O Enclosure and HA Card tell you where the port is. I0041 is a FICON port for a mainframe, and I0032, I0042 and I0052 are live FCP ports.

✅ Checkpoint: You found one FICON port and three live FCP ports, and know the enclosure of each.

4See who is logged in where

Run this:

lshostport -login

You should see this:

Date/Time: 24 October 2026 11:11:13 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
WWNN             WWPN             Host I/O ports ESSIOport
==========================================================
20000024FF2D0F86 21000024FF2D0F86 -    -         I0032
20000024FF2D0F87 21000024FF2D0F87 -    -         I0042
20000120FA13B914 10000090FA13B914 -    -         I0032
20000120FA13B915 10000090FA13B915 -    -         I0042

Two servers, each with two HBA ports. The WWPNs ending in 0F86 and 0F87 belong to one server (call it db01) and those ending in B914 and B915 to another (app07). The Host column is empty because no host objects exist yet, and you’ll create them in the Implementation course.

Now look at ESSIOport: every login lands on I0032 or I0042, and both of those are in enclosure 1B2.

✅ Checkpoint: You noticed that both hosts use only ports in enclosure 1B2.

5Check the cabling against the rule

Type quit to leave the shell. Now a script can check the cabling the way you would at work, reading the logins and port locations through the DS CLI and applying IBM’s rule.

A script can’t answer password prompts, so save your password in a password file first. If security.dat is already in your lab folder from an earlier lesson, skip this command (the shell would tell you the record already exists).

Run this (PowerShell):

python ds8sim.py -hmc1 10.0.0.1 -user admin -passwd YOURPASSWORD managepwfile -action add -name admin -pw YOURPASSWORD -pwfile security.dat

You should see this:

CMUC00206I managepwfile: Record 10.0.0.1/admin successfully added to password file security.dat.

Then save these eight lines as auto.profile in the same folder. banner: off, header: on and format: delim make every list come back as one header row plus comma-separated rows, which Python reads easily. Implementation Lesson 2 explains profiles in full.

auto.profile:

hmc1: 10.0.0.1
username: admin
pwfile: security.dat
devid: IBM.2107-78SV001
banner: off
header: on
format: delim
delim: ,

Save this checker as path_check.py on your laptop, in the lab folder next to ds8sim.py (it runs there, not on the DS8000). You give it a host name and the host’s WWPNs, and it finds where each WWPN is logged in with lshostport -login and looks up that port’s enclosure and card in lsioport -l.

# path_check.py - SaatVedha host path checker (rule from the IBM Redbook SG24-8559-01)
# Runs on your workstation or jump server, not on the DS8000.
# It talks to the DS8000 only through the DS CLI (auto.profile: banner off, header on, format delim).
# Rule: a host needs at least two connections to I/O ports on separate host adapters
# in separate I/O enclosures. The script reads the logins (lshostport -login) and the
# enclosure and card of each port (lsioport -l), so you only give it the host's WWPNs.
# Usage: python path_check.py <host> <WWPN> [<WWPN> ...]
import csv, subprocess, sys
DSCLI = ["python", "ds8sim.py", "-cfg", "auto.profile"]   # at work: ["dscli", "-cfg", "auto.profile"]

def dscli(*args):
    """Run one DS CLI command and return its rows as dictionaries."""
    out = subprocess.run(DSCLI + list(args), capture_output=True, text=True).stdout
    lines = [l for l in out.splitlines() if l and not l.startswith("SaatVedha") and not l.startswith("CMUC")]
    return list(csv.DictReader(lines))

if len(sys.argv) < 3:
    print("Usage: python path_check.py <host> <WWPN> [<WWPN> ...]")
    sys.exit(1)

host, wwpns = sys.argv[1], [w.upper() for w in sys.argv[2:]]
ports = {p["ID"]: p for p in dscli("lsioport", "-l")}
logins = dscli("lshostport", "-login")

paths = []                      # (wwpn, I/O port, card, enclosure)
for w in wwpns:
    mine = [l["ESSIOport"] for l in logins if l["WWPN"].upper() == w]
    if not mine:
        print(f"  {w} is not logged in to any DS8000 port")
    for io in mine:
        paths.append((w, io, ports[io]["HA Card"], ports[io]["I/O Enclosure"]))

encls = {p[3] for p in paths}
cards = {(p[3], p[2]) for p in paths}
print(f"Host {host}: {len(paths)} path(s), {len(cards)} host adapter(s), {len(encls)} I/O enclosure(s)")
for w, io, c, e in paths:
    print(f"  {w} -> {io} on card {c} in enclosure {e}")
ok = True
if len(paths) < 2:
    print("FAIL: fewer than two paths. One cable, port or switch failure stops this host."); ok = False
if len(cards) < 2:
    print("FAIL: all paths on one host adapter. A card replacement stops this host."); ok = False
if len(encls) < 2:
    print("FAIL: all paths in one I/O enclosure. An enclosure repair or code load can stop this host."); ok = False
if ok:
    print("PASS: two or more adapters in two or more I/O enclosures.")
sys.exit(0 if ok else 1)

Run this (PowerShell):

python path_check.py db01 21000024FF2D0F86 21000024FF2D0F87

You should see this:

Host db01: 2 path(s), 2 host adapter(s), 1 I/O enclosure(s)
  21000024FF2D0F86 -> I0032 on card C3 in enclosure 1B2
  21000024FF2D0F87 -> I0042 on card C4 in enclosure 1B2
FAIL: all paths in one I/O enclosure. An enclosure repair or code load can stop this host.

Two paths and two adapters, and it still fails. This is the most common hidden risk in DS8000 cabling, and the break lab shows you what it costs.

At work you keep each host’s WWPNs in a small list, and the jump server runs the checker for every host from cron or Task Scheduler after each zoning change.

✅ Checkpoint: The checker reports FAIL for db01 because both paths are in 1B2.