I have a disk inside my server which has failed and I'm trying to figure out which one it is. I did not make a list of all serial numbers as I should have. I plan on doing this but in the meantime, can I pull any additional information from the running system?

WARNING: Your hard drive is failing
Device: /dev/sdc [SAT], unable to open device

smartctl result:

$smartctl --all /dev/sdc
smartctl 6.2 2013-07-26 r3841 [x86_64-linux-3.10.0-514.2.2.el7.x86_64] (local build)
Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org

Smartctl open device: /dev/sdc failed: No such device

Since the disk is no longer online, is there someplace I can still query information on it?


Grepped dmesg for sdc:

$dmesg | grep sdc
[   12.074540] sd 0:0:2:0: [sdc] 5860533168 512-byte logical blocks: (3.00 TB/2.72 TiB)
[   12.074542] sd 0:0:2:0: [sdc] 4096-byte physical blocks
[   12.083407] sd 0:0:2:0: [sdc] Write Protect is off
[   12.083410] sd 0:0:2:0: [sdc] Mode Sense: 7f 00 10 08
[   12.084143] sd 0:0:2:0: [sdc] Write cache: enabled, read cache: enabled, supports DPO and FUA
[   12.798801]  sdc: sdc1 sdc9
[   12.807266] sd 0:0:2:0: [sdc] Attached SCSI disk
[716178.562173] sd 0:0:2:0: [sdc] Synchronizing SCSI cache
[716178.562252] sd 0:0:2:0: [sdc] Synchronize Cache(10) failed: Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK

Then grepped for those drives in fdisk:

$fdisk -l 2>/dev/null | egrep -i '^disk /dev+.' | grep 3.00 | sort
Disk /dev/sda: 3000.6 GB, 3000592982016 bytes, 5860533168 sectors
Disk /dev/sdd: 3000.6 GB, 3000592982016 bytes, 5860533168 sectors
Disk /dev/sds: 3000.6 GB, 3000592982016 bytes, 5860533168 sectors

I only have three 3TB disks in this system and they are all online. However the last one is all the way at the bottom of the fdisk list at /dev/sds. If a disk drops out and then comes back online is it reassigned the same dev id or a new one? This might be the drive.

  • I would think that it's the same dev id because it's connected to the same physical socket on the mainboard. Maybe you can get more info from your disks using hdparm -I /dev/sdc
    – Michael D.
    Jan 25 '17 at 7:59
  • hdparm -I results in /dev/sdc: No such file or directory.
    – Zhro
    Jan 25 '17 at 19:22
  • Usually the SATA ports on the mainboard have numbers 1,2,3. I would assume that 1 is sda, 2 sdb and so forth.
    – Michael D.
    Jan 26 '17 at 15:11
  • Try to do a hdparm -I on /dev/sda and /dev/sdb so you might get the serial numbers from drives that are working which leaves the defective drive.
    – Michael D.
    Jan 26 '17 at 15:14
  • The mystery is that it was reported that /dev/sdc was failing. But there is no device by that ID and all drives are online.
    – Zhro
    Jan 27 '17 at 5:26

If your drives have individual LEDs, you can generate some disk activity to make the LEDs light up with:

dd if=/dev/sdb of=/dev/null 

And try this on the responsive disks to find the bad disk by process of elimination.

  • Good answer! Although today most hard disks don't have leds already.
    – peterh
    Dec 9 '17 at 1:31
  • A lot of servers with front-panel disk slots still have some kind of indicator light.
    – bootbeast
    Dec 9 '17 at 2:16

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