I just started using unRAID on an old Qnap NAS I have which has a 32bit CPU, so I am running unRAID v5. When I was running the native Qnap OS, it had a capacity limitation, and I believe this was due to the 32bit CPU, that a single volume could be no larger then 16TB. Would unRAID running on this NAS have the same limitation?

No, your UnRAID array is not limited to this.  The only thing that MAY be an issue is if the disk controller on the QNAP doesn't have support for drives > 2TB.  UnRAID does NOT have this restriction -- that was the limit in v4, but v5 removed it;  but if your controller can't "see" the drives then you'll have that restriction.

 

But as long as you can "see" a drive larger than 2TB, then you can use any size drives you want, and UnRAID will support as large an array as you want to build.

 

Very simple to test this -- just put ANY drive > 2TB in and confirm it's seen okay 

 

Ok cool, my parity drive in the Qnap is 3TB so it can definitely see >2TB drives.

 

Thanks

The 16 TB limit that your QNAP sets is most likely a feature of the file system it uses. Some Drobo models had a similar limitation before their firmware was updated last year.

 

I used to run the EXT 4 file system on it when I was running the Qnap OS, I believe it was a combination of that file system and the 32bit CPU.

In any event, that restriction is now history 

 

... and since you know it can handle > 2TB drives, you can now stuff it full of 8TB, 10TB, or even 12TB drives and have some serious capacity in a tiny unit !!!    [Assuming, of course, that $$ is no object for the cost of your drives  ]