The January 2026 forum answer that USB disks could not be used to create ZimaOS RAID is now outdated. At the time, the user’s two 3TB USB HDDs were detected but did not appear in the storage-combine dialog, and another community member said only internal ZimaOS-formatted disks were supported for arrays.
Current ZimaOS documentation has since changed the boundary: USB drives are now described as usable for storage, array membership, or expanding existing storage space. That makes this thread useful mainly as a version-history example rather than a current limitation.
What Happened in the Original Thread?
The user was running ZimaOS 1.5.3 on a Dell OptiPlex with an internal system SSD, two external 3TB USB HDDs, and a 1TB NVMe drive. ZimaOS detected every disk, but the two USB HDDs were missing from the “create storage” selection.
A community reply said this was expected at that time and suggested USB-array support might arrive in a later release. There was no official IceWhale confirmation in the thread that gave a release date or guaranteed implementation.
Current ZimaOS Storage Behavior Is Different
The current ZimaOS storage setup now states that USB drives can be used as storage, added to an array, or used to expand an existing storage space. That directly supersedes the 1.5.3-era limitation described in the forum.
If your current system still detects USB disks but does not offer them in the array wizard, first confirm you are on the current ZimaOS release and that the disks are not already mounted, claimed by another pool, or holding data you still need.
Do Not Treat USB RAID Like Internal SATA RAID
Even when the UI allows USB disks in an array, the transport path is different. USB bridges, hubs, cables, enclosure power management and accidental unplugging add failure modes that direct SATA or NVMe connections do not have.
For always-on redundant storage, use the RAID versus backup guide to separate uptime from recovery, and the USB disconnect checklist before trusting an external enclosure under sustained RAID traffic.
How to Test a USB Array Safely
Use expendable data first. Confirm both disks remain visible through a reboot, copy a large test dataset, verify checksums, and watch for disconnect or reset events under sustained load. Then reboot again and confirm the array returns healthy without manual intervention.
If one USB bridge repeatedly disappears, do not keep rebuilding the array around it. Fix the physical transport problem first.
Bottom Line
The original report was valid for ZimaOS 1.5.3, but it is no longer the current rule. Modern ZimaOS documentation explicitly includes USB drives in storage arrays. The practical caution is no longer “USB RAID is impossible”; it is “USB RAID adds enclosure, cable and power risks that should be validated before production use.”
