ReadyNAS Ultra 6 won't boot

itsjasper wrote:
Repartition = i.e. create a new single partition. This is destructive and overwrites existing partition info.

Yes, I know what it does.

I'm saying that its better to restore the drive to an unpartitioned state, so the NAS thinks it is new. Otherwise OS4 might report a "corrupted root" error (and OS6 will require confirmation before it uses the disk).

I wasn't questioning your knowledge...

My reply was to your question as to whether the Mac Disk Utility did that; which it does, as well as allowing the partition to be deleted as MDGM says (Partition tab, highlight the partition, click the minus button below the partition display).

In my experience with several such situations of repurposing disks, I have found it matters not whether the Mac-formatted drive has zero or one partitions, across both OS4 and OS6. That was why I didn't state to 'remove all partitions'. Whether it is "better" is debatable as it seems open to interpretation (it's also easier and quicker to create a single partition, particularly if one isn't an advanced user). It's certainly a more thorough option, I'll agree.

Having said that, I'd generally do a disk format then erase the partition myself, but that's more because I secure erase disks and remove partitions before I put them away when they are not being used, out of habit.

The only time I've had issues has been where an existing ReadyNAS partition has still existed and was inserted without removing the partitions, but this was an error on my part due to incorrectly labelling a drive. Luckily it didn't cause an issue in my situation as the NAS alerted me.

There are several posts here where users have seen "corrupted root" messages when inserting a previously formatted disk with the NAS powered down. I've seen that once myself. So I recommend either simply deleting the partitions, or (equivalent) doing a quick or full erase with a low level diagnostic.

Generally the quick erase approach zeros some sectors at the beginning and the end, so the drive looks unformatted. The full erase diagnostic is an excellent disk test (and will pick up problems that the non-destructive tests miss), so if you want to verify the disk health anyway, it is a good approach.

There is no reason to do a secure erase before inserting drives in the NAS. The NAS re-formats anyway, and RAID setup will re-write every sector in the data volume partition. Doing a secure erase when you take them out of service is of course a good practice.

For others reading the thread - New SATA drives all have a built-in secure erase function. This is more effective than the software secure erase built into the NAS for a variety of reasons - one is that the drive firmware knows a lot more about where user data can be written than the NAS does (true with all drives, but especially the case with SSD). A second is that it is usually faster. Often accessing the internal secure erase function requires SATA or eSATA connections to the PC (USB adapters usually don't work for this). The built in ATA command is recommended by the most recent NIST recommendation for media sanitization (http://nvlpubs.nist.gov/nistpubs/Specia ... 0-88r1.pdf)