How to Resolve False Direct I/O Verification Failures in Hyperion

Written By Sebastian Sime (Administrator)

Updated at April 2nd, 2026

Table of Contents

Symptom Solution

→ Applies to: Hyperion 9.x and above

Symptom

After enabling Direct I/O on a dataset, the VM becomes unreachable and is found in a "Paused" state within the hypervisor due to false "Direct I/O verification" failures. Upon resuming the VM, the guest system time is out of sync compared to the actual time zone.

Solution

Step 1. Connect to Hyperion appliance via SSH as admin

ssh admin@<your_ip_address_or_hostname>

Step 2. Become Super User

sudo su

Step 3. Disable DIO globally

echo 0 > /sys/module/zfs/parameters/zfs_dio_enabled

Step 4. Make the change persistent

echo 'options zfs zfs_dio_enabled=0' >> /etc/modprobe.d/zfs.conf

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Symptom

Solution

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