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Question

Phoenix fails with “Cannot read: Input/output error” while reinstalling NX node after power outage

  • September 1, 2026
  • 2 replies
  • 34 views

Hi Everyone.

I have a 4-node Nutanix NX demo/POC cluster running AHV. After a power outage at the office, the cluster did not recover properly.

Initial situation:

  • 4-node Nutanix NX cluster
  • Hypervisor: AHV
  • This is a POC environment, so there is no important data to recover
  • After the outage, only the CVM on Node A was active
  • Nodes B, C and D only booted into AHV
  • On Nodes B, C and D, virsh list --all did not show any CVM

What I already tried:

  • I generated a Phoenix ISO from the working CVM using the AHV ISO and Nutanix/AOS installer package
  • The generated Phoenix ISO is around 6 GB
  • I used that same Phoenix ISO successfully on Node B
  • On Node B, I selected “Wipe data and install CVM + hypervisor” and the node was reinstalled successfully
  • However, Node C and Node D fail during the same Phoenix reinstall process

Phoenix error on Node C:

tar: /mnt/local/images/svm/nutanix_installer_package-release-euphrates-5.20.0.1-stable-f5e54bf50b9b92d1e27560e422629e322968a3e0-x86_64.tar: Cannot read: Input/output error
tar: Too many errors, quitting
tar: Error is not recoverable: exiting now
FATAL An exception was raised:
StandardError: Failed command: [tar xvf /mnt/local/images/svm/nutanix_installer_package-release-euphrates-5.20.0.1-stable-f5e54bf50b9b92d1e27560e422629e322968a3e0-x86_64.tar -C /mnt/svm_installer --totals] with reason [None]

Additional Foundation issue:
I also tried Nutanix Portable Foundation, but it fails connecting to the IPMI interfaces.

IPMI addresses:

  • Node A: 172.16.70.213
  • Node B: 172.16.70.214
  • Node C: 172.16.70.215
  • Node D: 172.16.70.216

Foundation error:

Failed to connect to the following IPMIs:
172.16.70.213, 172.16.70.214, 172.16.70.215, 172.16.70.216

Network/IPMI tests:

  • Ping to all IPMI addresses works
  • I can access the IPMI web interface using HTTP/port 80
  • TCP 443 works only on 172.16.70.213
  • TCP 443 fails on 172.16.70.214, 172.16.70.215 and 172.16.70.216
  • I tested Portable Foundation from a Windows Server
  • I also tested Portable Foundation from a laptop connected to the same switch and same VLAN as the IPMI ports, but the same error occurs

USB boot issue:

  • I created a bootable USB using BalenaEtcher with the Phoenix ISO
  • I connected it to the rear USB ports of the Nutanix node
  • In the boot menu, the USB device did not appear as expected
  • I only saw a SanDisk option, but selecting it booted the existing AHV installation
  • I tried multiple rear USB ports with the same result

Current goal:
Since this is only a POC cluster, I do not need to recover the old data. I just need to reinstall/rebuild Nutanix from scratch, even if the cluster is empty.

Questions:

  1. Why would Phoenix fail with “Cannot read: Input/output error” on Node C/D while extracting the AOS/SVM installer package, if the same ISO worked successfully on Node B?
  2. Could this indicate a local disk, SATADOM/boot device, USB/virtual media, RAM, or BMC issue on Nodes C/D?
  3. What is the recommended way to fully wipe and reinstall all 4 nodes with AHV + CVM?
  4. For the Foundation IPMI error, should HTTPS/Web SSL be enabled or disabled on older NX IPMI firmware?
  5. Is there a recommended way to validate IPMI/RMCP+ connectivity from Windows before running Foundation?

Any guidance on how to proceed with a clean rebuild would be appreciated.

2 replies

Forum|alt.badge.img+3
  • Trailblazer
  • September 4, 2026

Way to go with all the details!  This appears to be a hardware issue as an Input/output error failure in Phoenix is most likely related to a hardware issue with the drive or drive subsystem.
Try to identify and reseat or replace the disk:
    You may see foundation Error:
“Fatal: Running CVM installer, starting host installer”
    or in phoenix Console/Log Trace:
ERROR svm.py:269 Failed to format /dev/sda. Traceback:
...
os.fsync(d.fileno())
OSError: [Errno 5] Input/output error
    For NVMe drives:
the error may appear as Failed to format /dev/nvmeXXX during the “Zeroing the superblock” step
    Smartctl Failure:
Running smartctl -x /dev/sdX on the reported disk in Phoenix mode returns Smartctl open device: /dev/sda failed: INQUIRY failed
 


JeroenTielen
Forum|alt.badge.img+8
  • Vanguard
  • September 5, 2026

If you want to reinstall make sure you use foundation. (not phoenix iso). I always have the best results with the foundation vm and not running foundation direct on windows or macos. Make sure your foundation vm can talk to the ipmi's and the ahv/aos vlans.