I am setting up a ZFS NAS using Ubuntu 18 with 8 hard drives for storage. When I use sudo lsblk -P to check what the drive names are, I only see sdb-sdh. I know this is because it will skip over the drives that are a size 0. I did sudo lsblk -Pa and then I see sda, but SIZE="". My question is, does SIZE="" mean that this drive is bad and needs to be replaced, or is there something else that needs to be done with this drive that I am not aware of? Thank you for your help.

Image of lsblk -Pa

enter image description here

Update After typing in sudo smartctl -iHAf brief -l error -l xerror /dev/sda this is the output:

smartctl 6.6 2016-05-31 r4324 [x86_64-linux-4.15.0-52-generic] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

Vendor:               SEAGATE
Product:              DKS2D-H3R0SS
Revision:             4F09
User Capacity:        2,983,000,009,600 bytes [2.98 TB]
Logical block size:   520 bytes
Rotation Rate:        7200 rpm
Form Factor:          3.5 inches
Logical Unit id:      0x5000c50056efa9cf
Serial number:        Z2987NX20000C3515M22
Device type:          disk
Transport protocol:   SAS (SPL-3)
Local Time is:        Sun Jun 23 13:46:00 2019 UTC
SMART support is:     Available - device has SMART capability.
SMART support is:     Enabled
Temperature Warning:  Enabled

SMART Health Status: OK

Current Drive Temperature:     46 C
Drive Trip Temperature:        68 C

Manufactured in week 29 of year 2013
Specified cycle count over device lifetime:  10000
Accumulated start-stop cycles:  191
Specified load-unload count over device lifetime:  300000
Accumulated load-unload cycles:  191
Elements in grown defect list: 1

Vendor (Seagate) cache information
  Blocks sent to initiator = 815387184
  Blocks received from initiator = 128354709
  Blocks read from cache and sent to initiator = 0
  Number of read and write commands whose size <= segment size = 3123587
  Number of read and write commands whose size > segment size = 0

Vendor (Seagate/Hitachi) factory information
  number of hours powered up = 16529.18
  number of minutes until next internal SMART test = 47

Error counter log:
           Errors Corrected by           Total   Correction     Gigabytes    Total
               ECC          rereads/    errors   algorithm      processed    uncorrected
           fast | delayed   rewrites  corrected  invocations   [10^9 bytes]  errors
read:   1509905219        0         0  1509905219          0        424.001           0
write:         0        0         0         0          0         66.846           0
verify:   306677        0         0    306677          0          0.000           0

Non-medium error count:       89

[GLTSD (Global Logging Target Save Disable) set. Enable Save with '-S on']

1 Answer 1


Yes, it might well mean the drive is bad. Some disk drives indicate that they are failing their internal diagnostics by reporting their size as zero, others may respond to commands with a "no media inserted" error code in the same situation.

You probably should check the SMART status of the disk: smartctl -iHAf brief -l error -l xerror /dev/sda should output a concise report of the most important SMART disk health information.

Also, you might want to look at the output of dmesg -H for error messages.

  • Thank your for your advice, I ran the smartctl check you mentioned, and I have updated my question with the output of that report. It says status is OK. Could there be other indications that would show the drive is bad? If it is not bad, is there a way to get it to be use able? I can't even write zeros using dd to it.
    – laxer
    Commented Jun 23, 2019 at 13:52
  • I also looked at the output of dmesg -H but I didn't see any errors
    – laxer
    Commented Jun 23, 2019 at 13:53

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .