WD external USB HD not detected/mounted by my NAS WDmycloudEX4

My Cloud OS 3 Personal & Network Attached Storage My Cloud EX4
1

The external disk is a WD Elements 4TB one; I thought it would be easy being of the same brand; not at all.

I reformatted the disk with my linux desktop box to have two partitions of 2TB each, and filesystem was EXT4.

The NAS didn’t mount it until the file system was NTFS. NTFS is not suitable because the ext4 carries more information, so doing the backup I woud lose something (example, ntfs can’t handle filenames with a leading . (dot).

dmesg output is

[...]
EXT4-fs (sdc1): couldn't mount RDWR because of unsupported optional features (400)
EXT4-fs (sdc2): couldn't mount RDWR because of unsupported optional features (400)
FAT-fs (sdc): bogus number of reserved sectors
FAT-fs (sdc): Can't find a valid FAT filesystem
ufsd:
ufsd:======NTFSBoot->le(0)======
ufsd:Signature         : 0x0000000000000000
ufsd:RWBlocks          : 0x3a37f700 x 0x1000, sdc, rw
ufsd:SectorsPerVolume  : 0x0 x 0x0
ufsd:SectorsPerCluster : 0x0
ufsd:MFT               : 0x0
ufsd:MFTMirr           : 0x0
ufsd:Record size       : 0
ufsd:Index size        : 0
ufsd:Magic             : 0x55aa
ufsd:===========================
ufsd:Invalid NTFS boot signature
ufsd:
ufsd:=== HfsVolumeHeader->le =========
ufsd:Signature         : \xffffffaf=
ufsd:Version           : 50703
ufsd:Attributes        : 0x83847247
ufsd:LastMounted       : \xffffff8ey=i
ufsd:BytesPerBlock     : 0xffdfdfe8
ufsd:Invalid HFS+ signature at 0
ufsd: failed to mount "sdc"
usb 2-2: USB disconnect, device number 2
hotPlug.sh begin(seq=763)...
hotPlug.sh end(seq=763).
usb 2-2: new SuperSpeed USB device number 3 using etxhci_hcd_131016
scsi5 : usb-storage 2-2:1.0
scsi 5:0:0:0: Direct-Access     WD       Elements 25A3    1021 PQ: 0 ANSI: 6
sd 5:0:0:0: [sdc] Spinning up disk...
sd 5:0:0:0: Attached scsi generic sg2 type 0
..........ready
sd 5:0:0:0: [sdc] Very big device. Trying to use READ CAPACITY(16).
sd 5:0:0:0: [sdc] 7813969920 512-byte logical blocks: (4.00 TB/3.63 TiB)
sd 5:0:0:0: [sdc] 4096-byte physical blocks
sd 5:0:0:0: [sdc] Write Protect is off
sd 5:0:0:0: [sdc] Mode Sense: 47 00 10 08
sd 5:0:0:0: [sdc] No Caching mode page present
sd 5:0:0:0: [sdc] Assuming drive cache: write through
sd 5:0:0:0: [sdc] Very big device. Trying to use READ CAPACITY(16).
sd 5:0:0:0: [sdc] No Caching mode page present
sd 5:0:0:0: [sdc] Assuming drive cache: write through
 sdc: sdc1 sdc2
sd 5:0:0:0: [sdc] Very big device. Trying to use READ CAPACITY(16).
sd 5:0:0:0: [sdc] No Caching mode page present
sd 5:0:0:0: [sdc] Assuming drive cache: write through
sd 5:0:0:0: [sdc] Attached SCSI disk
hotPlug.sh begin(seq=783)...
hotPlug.sh end(seq=783).
EXT4-fs (sdc1): couldn't mount RDWR because of unsupported optional features (400)
EXT4-fs (sdc2): couldn't mount RDWR because of unsupported optional features (400)
FAT-fs (sdc): bogus number of reserved sectors
FAT-fs (sdc): Can't find a valid FAT filesystem
ufsd:
ufsd:======NTFSBoot->le(0)======
ufsd:Signature         : 0x0000000000000000
ufsd:RWBlocks          : 0x3a37f700 x 0x1000, sdc, rw
ufsd:SectorsPerVolume  : 0x0 x 0x0
ufsd:SectorsPerCluster : 0x0
ufsd:MFT               : 0x0
ufsd:MFTMirr           : 0x0
ufsd:Record size       : 0
ufsd:Index size        : 0
ufsd:Magic             : 0x55aa
ufsd:===========================
ufsd:Invalid NTFS boot signature
ufsd:
ufsd:=== HfsVolumeHeader->le =========
ufsd:Signature         : \xffffffaf=
ufsd:Version           : 50703
ufsd:Attributes        : 0x83847247
ufsd:LastMounted       : \xffffff8ey=i
ufsd:BytesPerBlock     : 0xff070000
ufsd:Invalid HFS+ signature at 0
ufsd: failed to mount "sdc"
EXT4-fs (sdc1): couldn't mount RDWR because of unsupported optional features (400)
[...]

Am I doing something wrong? I don’t think so, nut it is not working,

Does anybody have a suggestion?

Thanks

2

Hi mune,

The WD My Cloud External USB feature supports the the below mentioned file format

1.) FAT32
2.) NTFS
3.) HSF+
4.) exFAT (In some cases).

3

It should support ext4, too, being a linux system.

I got it working a couple of days ago!

With my Ubuntu linux box using gparted I delete the original partition and create two ones of 2 TB each and I formatted both with EXT4 (not sure it was needed)

Then I attached the USB disk on the NAS. Using dmesg I got what device (/dev/sdX) the NAS was unable to mount.

Then I reformatted the partitions:

root@WDMyCloudEX4 root >  mkfs.ext4 /dev/sdc1
root@WDMyCloudEX4 root > mkfs.ext4 /dev/sdc2

Finally I found the two new USB devices (I don’t remember if I reboot the NAS or just waited):

root@WDMyCloudEX4 root > ls /mnt/USB/
USB2_c1  USB2_c2

Now I’m following this guide [GUIDE] How to Make Persistent System Changes (crontab, etc) to use rsync to backup my NAS shares.

4

Too easy! :frowning:

I followed that guide and at very end a reboot is requested, so I did it. When the NAS went up again, it didn’t mount the ext4 USB partition.

I created a mount point and mounted it

root@WDMyCloudEX4 Public > mkdir ext4_1
root@WDMyCloudEX4 Public > mount /dev/sdc1 /mnt/USB/ext4_1

It is fine for my backup script but each time there is a power loss or a reboot for any reason, I have to manually remount it. What a hassle!