I can write ~100MB/s on a particular 4TB SAS drive when it have a file system on it, but a low level format on this drive took >16 hours. That's ~70kB/s. Since there is not filesystem and only zeroes have to be written, I would have expected better performance then with a filesystem.
The LLF was done in a HP MDS600 (D6000) JBOD in its onboard RAID utility.
Why does a low level format take so long?