I have carried out a proof of concept RAID 1 NAS using two 8GB Toshiba USB memory sticks. When using new 2TB ones however I get various error warnings when using fdisk to create the GPT partition. Creating the array and then mkfs.ext4 to format it seems to work OK but then it gives errors and refuses to mount. fsck -ydd finds and says it fixes lots of errors but makes no difference. The same applies if I format the individual memory stick rather than creating the array. They both seem to work perfectly with exFAT format on my Win11 laptop. My question is, could there be something in ROM on the memory stick specific to exFAT that is preventing using GPT and ext4?

AlanZZZ wrote: ↑

Thu Oct 30, 2025 10:47 am

My question is, could there be something in ROM on the memory stick specific to exFAT that is preventing using GPT and ext4?

No. USB storage devices implement MSC (Mass Storage Class) or UAS (USB Attached SCSI) protocols, which are neutral with regard to partitioning and formatting standards. However, there could perhaps be firmware bugs in the implementation that are more likely to trigger in less common usages.

You should have noted the text of the various errors and warnings (and error warnings, whatever that might mean). With no information, we cannot even rule out user error.

Thanks. It says things like backup GPT is corrupt using primary. When trying to mount it says wrong fs type, bad option, bad superblock on /dev/xxx, missing codepage our helper program or other error. I have successfully partitioned one as MBR primary and formatted mkfs.exfat and it mounted successfully. I think I am going to try creating the array using exfat as I am not interested in special file permissions as only I will be using it. Currently I am busy copying files to one of them on my laptop until it is full but 2TB will take a lot of hours.

I copied loads of data to the drive on my Win 11 laptop. When it reached about 1TB it bombed out with an unknown error and most of the directories and files "disappeared" . I suspect that the drive that I bought on ebay fairly cheaply was much less than 2TB but masquerading as that and able to fool Win11 but had problems when trying to partition using GPT and format using ext4. In file explorer properties it shows as a model of Western Digital ssd that is 1TB. I have told the vendor and asked for a refund.