Mounting 2TB+ USB3 disk on 1.04.04 firmware mountable but still has 2TB limit issue

My Cloud OS 3 Personal & Network Attached Storage My Cloud EX2
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  1. Apricorn Padlock DT 3.0TB USB3 disk is now mountable on 1.04.4 firmware, it was not possible before this version.

  2. the 3TB drive was formated on centos 6.5 with /dev/sdb1 as linux fs and init with ext4 fs type, it shows 3TB capacity.

  3. moving the disk to EX2 with  1.04.4 firemware and it was able to be auto mounted, but still it only show 2TB in size.

  4. See following detail from “demsg” and “df -h” output.

usb 4-1: new SuperSpeed USB device number 9 using xhci_hcd
scsi3 : usb-storage 4-1:1.0
scsi 3:0:0:0: Direct-Access Apricorn Padlock DT 3.0 0120 PQ: 0 ANSI: 6
sd 3:0:0:0: [sdc] Very big device. Trying to use READ CAPACITY(16).
sd 3:0:0:0: [sdc] 5860533168 512-byte logical blocks: (3.00 TB/2.72 TiB)
sd 3:0:0:0: [sdc] 4096-byte physical blocks
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
sd 3:0:0:0: Attached scsi generic sg2 type 0
sd 3:0:0:0: [sdc] Write Protect is off
sd 3:0:0:0: [sdc] Mode Sense: 2b 00 10 08
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
sd 3:0:0:0: [sdc] Write cache: enabled, read cache: enabled, supports DPO and FUA
sd 3:0:0:0: [sdc] Very big device. Trying to use READ CAPACITY(16).
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
 sdc: sdc1
sd 3:0:0:0: [sdc] Very big device. Trying to use READ CAPACITY(16).
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
xhci_hcd 0000:00:00.0: WARN: Stalled endpoint
sd 3:0:0:0: [sdc] Attached SCSI disk
EXT4-fs (sdc1): mounted filesystem with ordered data mode. Opts: (null)
~ # df -h |grep c1
/dev/sdc1 2.0T 198.0M 1.9T 0% /mnt/USB/USB1_c1
~ #

 5. Question, is this just display error on size ? Can I really write to sdc1 upto 3TB safely ?

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tjyang - I am quite sure it’s not a display error…your attached USB drive indeed only offers you total 2TB capacity.

My best guess is that this isn’t a problem with the WD EX2…because EX2 recognizes the full capacities of both my attached 4TB USB (Windows 7 NTFS-formatted) drives, one from WD and one from Toshiba. I suspect this is the 2TB limitation many older OS’ have with recognizing and formatting drives bigger than 2TB. They only format 2TB of space. So I would check when you attach this drive into CentOS 6.5, what capacity do you get. I may be wrong, but my hunch is it’ll be 2TB. If that’s the case, then you have two options:

  1. Probably the latest CentOS 7 supports 2+ TB drives…you may have to upgrade to that, if that’s what you find on researching.
    OR
  2. Attach the drive to a Windows 7 or 8 PC and format it as NTFS, which will offer you full 4TB, and then attach the NTFS formatted drive to EX2, where you’ll still be able to continue using the 4TB space.
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Cybernut1 wrote:
tjyang - I am quite sure it’s not a display error…your attached USB drive indeed only offers you total 2TB capacity.

My best guess is that this isn’t a problem with the WD EX2…because EX2 recognizes the full capacities of both my attached 4TB USB (Windows 7 NTFS-formatted) drives, one from WD and one from Toshiba.> Glad to know WD and Toshiba 4TB NTFS drives can be mounted. May be the Apricorn hardware encryption introduce this issue. I tried follow ing win7 formatting procedure but still the 3TB can’t be mounted.> In the end I format the drive with GPT/Mac HFS using my Macbook Pro’s Disk utility. the 3TB space was able to mounted on EX4 finally !!> Thanks for your reply> I suspect this is the 2TB limitation many older OS’ have with recognizing and formatting drives bigger than 2TB. They only format 2TB of space. So I would check when you attach this drive into CentOS 6.5, what capacity do you get. I may be wrong, but my hunch is it’ll be 2TB. If that’s the case, then you have two options:

  1. Probably the latest CentOS 7 supports 2+ TB drives…you may have to upgrade to that, if that’s what you find on researching.
    OR
  2. Attach the drive to a Windows 7 or 8 PC and format it as NTFS, which will offer you full 4TB, and then attach the NTFS formatted drive to EX2, where you’ll still be able to continue using the 4TB space.
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If you wouldn’t mind tjyang, could you please give me a kudo on my previous post (not this one) by clicking on the star to the left of that post and also marking that post as a solution. Helps to identify this solution for other community users with a similar problem when searching for issues similar to theirs. Thanks.

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