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Replacing the CMOS Battery in C-72T, C-168T, K-144T, and K-168T Nodes

⚠️ Important: The C-72T, C-168T, K-168T, and K-144T platforms will reach their End of Platform Support (EoPS) on January 30, 2028.


This article explains how to replace the CMOS battery in the C-72T, C-168T, K-144T, and K-168T nodes and reapply the BIOS settings.

Important: The BIOS settings stored in volatile memory are lost when you remove the power distribution unit (PDU) and CMOS power from the node. After you replace the CMOS battery, you must reapply the BIOS settings and reconfigure the out-of-band management (IPMI) port to bring the node back online.


  • Low-voltage CMOS battery
  • CR2032 coin cell battery from Qumulo Care for each applicable node
  • Bootable USB drive flashed with minimum Qumulo Core 6.2.1 installer image
    Note: To obtain the image, contact Qumulo Care. For more information see Create a Qumulo Core USB Installer Key.
  • Crash cart (KVM) for accessing the node


Step 1: Prepare for CMOS Battery Replacement

Before you bring a node offline to replace the CMOS battery, you must check that the cluster is in a healthy state.

  1. Log in to your cluster's Web UI and ensure that there are no warning banners on the dashboard and that the Protected icon appears in the upper right.
    Important: If the Protected icon doesn't appear on the dashboard, don't try to replace the CMOS battery.
  2. Download the Qumulo USB Installer image.
    Note: The Python script that reinstalls the BIOS settings disregards the Qumulo Core version, as long as you run Qumulo Core version 3.3.0 (and higher) that supports Python 3.x.
  3. To build the Qumulo USB Installer drive, see Create a Qumulo Core USB Installer Key.

Step 2: Power off and Prepare the Node for Replacement

  1. Log in to the target node via SSH or Crash Cart (KVM) and assume root privileges by using the sudo -s command.
  2. Power off the node by using the shutdown -h now command.
    This puts the cluster in an N-1 state for the duration of the work on this node.
    Note: All Qumulo clusters are designed to tolerate a node going offline. If your cluster is healthy, it remains operational for the duration of the work.
  3. When the node is off, disconnect all cables from it.
    Note: Before you disconnect network fiber cables, we recommend labeling the ports to which the cables correspond.

Step 3: Replace the Battery in the Node

  1. On the front of the node, loosen the two black thumbscrews and then pull the node out of the rack.
  2. To remove the panel, press the blue button and then slide the panel cover towards the back of the node.
  3. To remove the battery assembly, gently pull straight up from the connector and then connect the replacement battery assembly to the motherboard.
    Important: Make sure that you align the connector properly.
  4. Place the air baffle back in its original position and then place the cover back on the node.
  5. Position the cover and slide it towards the front of the node.
    Important: Make sure that the peg underneath the cover aligns with the opening on the enclosure.
  6. Reinstall the node in the rack, reconnect all cables, tighten the two black thumbscrews on the front of the node, and secure the node to the rack.
    Important: Do not power on the node yet.

Step 4: Reinstall the BIOS Settings

  1. Insert the Qumulo Core USB Installer drive into the node.
  2. Power on the node.
  3. To enter the boot menu, press F11.
  4. Select your Qumulo Core USB Installer drive from the list of devices and then press Enter.
    The node boots to a command line.
  5. Type the sudo -s command.
  6. Enter the default password, Admin123.
  7. To flash the BIOS configuration to its default settings, use the following command.

Step 5: Reboot Your Node and Add it to the Quorum

  1. To reboot your node, use the ipmitool power cycle command.
  2. Remove the USB Installer drive from the node.
  3. To ensure that all nodes are in quorum, check the cluster's Web UI.
  4. Before you proceed with any additional replacements, ensure that the restriper process completes by using the qq restriper_status command.
  5. When all nodes are in quorum and the restriper process completes, repeat this process for any other nodes in the cluster.

Step 6: Restore IPMI Configuration

Power loss causes IPMI configuration to be lost. For instructions on restoring IPMI configuration, see the IPMI Reference Guide and the IPMI Reference Guide for K-144T and K-168T.

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