Multible USB HD's are not show in storrage/drive

[Fleshmauler]

Why you should avoid USB attached drives for data pool disks

This subject has been coming up quite often since about 2022. Perhaps because of TrueNAS SCALE has brought forth some attention to TrueNAS in general and ZFS in specific. Please note that this is about USB attached storage for ZFS data pools. On occasion, people use USB drives, (flash, USB->SATA, USB->NVMe, etc…), for booting. In general, these do work acceptably, (when not using the cheapest USB flash drives). Though, it is always recommended to backup your configuration in case of boot drive …

If I had to guess you’re impacted by:

USB attached SATA disks may use the same serial number, confusing software that attempts to detect multipathed disks.

Edit:
// If sata ports are unavailable or limited on the machine I’d strongly recommend getting a cheap LSI HBA with firmware flashed to IT mode for ~$30 USB on ebay instead of continuing to try getting USB HDDs working. You’ll save yourself a lot of time & lost data.

I also can’t find that specific model of OptiPlex, but I’m hoping you got at least 1 free Pcie slot available somewhere in there. Don’t forget to slap a fan in pointing at the HBA.