ReadyNAS Pro 4 & WD MyBook Duo - wrong drive size

Page 50 of the manual says
[quote="http://www.downloads.netgear.com/files/GDC/RNDU2000/ReadyNAS_Business_SW_05Nov13.pdf":1vojnqx2]...Partitions on the storage devices must be one of the following file system formats: FAT32, NTFS, EXT2, EXT3...[/quote:1vojnqx2]

You can format a normal USB drive from the NAS admin UI, but I don't know that would work with the MyBook Duo.

When I ssh to my NAS, and do an LS, I see the following:

GeoffNAS://# ls -l
total 23068
lrwxrwxrwx 1 root root 16 2010-03-15 19:48 addons-config -> /c/addons-config
lrwxrwxrwx 1 root root 10 2013-12-11 16:01 Backups -> /c/Backups
drwxr-xr-x 2 root root 4096 2014-10-12 19:52 bin
drwxrwxrwx 17 root root 4096 2014-12-16 10:32 c
drwxr-xr-x 17 root root 4740 2014-12-30 20:26 dev
drwxr-xr-x 75 root root 4096 2014-12-30 20:26 etc
-rw-r--r-- 1 root admin 23500800 2014-03-01 18:42 files.tar
drwxr-xr-x 6 admin admin 4096 2009-10-02 19:15 frontview
-rw-r--r-- 1 root admin 84 2011-12-05 22:45 GeoffNAS_00223FA9CC14
drwxr-xr-x 4 root root 4096 2008-03-11 20:56 home
-rw-r--r-- 1 root root 37 2011-11-13 22:50 hu ??v ?LogF?
drwxr-xr-x 2 root root 4096 2007-09-07 13:53 initrd
lrwxrwxrwx 1 root root 9 2012-02-13 16:59 iTunes -> /c/iTunes
lrwxrwxrwx 1 root root 12 2013-04-28 23:14 KR-Photos -> /c/KR-Photos
drwxr-xr-x 14 root root 4096 2014-10-12 19:52 lib
drwxr-xr-x 2 root root 4096 2014-10-12 19:52 lib64
drwx------ 2 root root 16384 2010-03-11 12:19 lost+found
lrwxrwxrwx 1 root root 8 2013-09-22 19:03 media -> /c/media
drwxr-xr-x 2 root root 4096 2006-10-28 10:06 mnt
drwxr-xr-x 2 root root 4096 2010-03-15 19:44 Monitor
drwxr-xr-x 6 root root 4096 2011-06-27 19:20 opt
dr-xr-xr-x 133 root root 0 2014-12-30 20:25 proc
drwxrwxrwt 2 root root 0 2014-12-30 21:53 ramfs
lrwxrwxrwx 1 root root 12 2014-12-28 00:45 RNXconfig -> /c/RNXconfig
drwxr-xr-x 3 root root 4096 2014-10-12 19:52 root
drwxr-xr-x 2 root root 4096 2014-10-12 19:53 sbin
lrwxrwxrwx 1 root root 11 2010-03-11 19:13 Software -> /c/Software
drwxr-xr-x 12 root root 0 2014-12-30 20:25 sys
lrwxrwxrwx 1 root root 7 2010-03-11 19:14 Temp -> /c/Temp
drwxrwxrwt 10 root root 4096 2014-12-30 21:39 tmp
lrwxrwxrwx 1 root root 11 2010-03-11 19:13 Torrents -> /c/Torrents
drwxrwxrwt 3 root root 60 2014-12-30 20:26 USB
lrwxrwxrwx 1 root root 14 2012-02-06 21:49 USB_HDD_1 -> /USB/USB_HDD_1
lrwxrwxrwx 1 root root 14 2014-12-30 20:26 USB_HDD_3 -> /USB/USB_HDD_3
drwxr-xr-x 12 root root 4096 2009-01-14 09:52 usr
drwxr-xr-x 17 root root 4096 2014-10-12 19:53 var
lrwxrwxrwx 1 root root 10 2010-03-15 19:48 webroot -> /c/webroot
GeoffNAS://#

I will note that the Frontview Control Panel shows USB_HDD_3, and not USB_HDD_1... so the NAS can see both, but is choosing to focus on 3, for some reason. And I can't seem to change that from my laptop (OS X 10.10), no matter what I do.

I finally figured this out, although it was a bit of a challenge.

Mac OS X was throwing a small EFI partition at the front of the drive, that the NAS was picking up on. Even when I used a formatting tool to remove it and create a single partition, then NAS did not want to format the new partition, even from a command line using SSH.

The trick was to connect the USB drive to a Linux system, repartition it down to one partition, and then format it in EXT4 *before* attaching it to the NAS. In my case, I used an Unbuntu VM downloaded for free from Parallels, but one can also easily boot from a GParted CD and use that. Make sure you create, and format, the partition before you attach the drive to the NAS.

Once that was done, the NAS saw the drive, the correct partition, and was able to reformat it on its own (my check to make sure it was happy). I noted that I only have 11 TB listed, not 12... might be a limitation of how ETX4 is set up on the drive (it's still more than enough to back up 9 TB from the NAS!)

Thx for sharing. I was thinking there was an small partition getting in the way, but wasn't sure how to overcome that on the Mac (since I'm a windows guy). And I didn't want to give you advice that might brick your mybook.

The NAS UI reports in TiB, not TB. 12 TB == 10.9 TiB, so that likely accounts for the discrepancy. You can confirm with SSH on the NAS of course.