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QuantumMechanic

Disk disappears from array on reboot

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Posted (edited)

Hi all,

 

Recently bought unRAID for a new system I set up for NAS and some docker services. Loving it so far, almost everything's worked perfectly.

 

The only issue I'm having is that when I reboot the server, one of my drives gets dropped from the array, and I have to go through the process of adding it back to the array and rebuilding the disk from parity.

 

All four of my drives are in a non-RAID HDD enclosure connected via USB 3.1. I have identical WD Red 4TB drives for parity and first storage drive, an older 2 TB WD Blue I had lying around for second storage and a 4 TB Seagate Barracuda that had been a backup drive in my desktop for the last storage drive. The Barracuda was added after I originally put the server together, and it is the one that drops out on reboot. None of my other drives do this.

 

I've attached the syslog and drive SMART report. This isn't a vital issue but I don't want to wear out my drives doing this every time I have to reboot the server. Any insight would be appreciated.

montpellier-syslog-20190714-0913.zip montpellier-smart-20190714-1911.zip

montpellier-diagnostics-20190714-2211.zip

Edited by QuantumMechanic

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2 hours ago, QuantumMechanic said:

 All four of my drives are in a non-RAID HDD enclosure connected via USB 3.1. 

 

USB, though allowed, is not recommended for array or cache due to unreliability in some cases. Best to reconsider your design. 

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I respect it isn't ideal but I don't have an alternative at this point. None of the other drives are having this issue, though, which is why I asked about it. If other drives dropped out on reboot I'd say it's because of the USB but it's only the one I swapped in later.

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Posted (edited)

USB3 has been a headache for Unraid for a long time.   Because so few people use it for array drives, it usually crops up as a problem with the Unraid boot drive.  The universal solution for these problems has been to use a USB2 port for the boot drive.  (I don't have a real answer as to why these problems happen but I suspect it is because some MB's  (or BIOS's) start up all USB3 ports in USB2 mode and when the OS starts to boot, it detects them as UBS3 and install the USB3 driver.  Somewhere in this handoff, the information that the drive has been detected by the BIOS is lost.) 

 

Have you looked to see if you could use an esata solution.  (Do a search on Amazon or Monoprice for 'sata to esata' and you will see some of the items that are available.)   Take a look at that HDD enclosure and there might be a way to utilize it with esata cables.

Edited by Frank1940

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5 minutes ago, Frank1940 said:

USB3 has been a headache for Unraid for a long time

It's a headache on all systems.  Ever notice how on occasion a bare metal Windows install will on occasion do the USB disconnect / reconnect sound when it's just sitting there doing nothing?  Especially if you have multitude of devices connected.

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e-SATA isn't an option for this particular enclosure. At some point when I have the space I'll have them all wired internally but this is 99% working for now, aside from this one issue.

Like I said before, though, I haven't had a problem with the other three drives at any point - if the USB were the problem, though, wouldn't all the drives be having this issue, or at least different ones at various points? It's literally just one drive out of the four in the enclosure - as I said, one that I put in later on. Might also be worth noting I had to move to a new USB key not too long after installing that drive, and though it seemed to copy all my settings over okay, could that be why it falls out of the array on reboot?

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I'm looking at the system log, and it doesn't appear to be having any trouble seeing or mounting the drive on reboot, but when it comes to the "import" command there aren't any additional flags for it like there are for the other three array disks. I really don't think this is an issue with USB in this case. It's like unRAID has forgotten that there's supposed to be a fourth disk in the array.

Device inventory:

WDC_WD20EZRZ-00Z5HB0_WD-WMC4N0M4VXSX (sdd) 512 3907029168

ST4000DM004-2CV104_ZFN0WKQM (sde) 512 7814037168 (this is the Seagate drive)

WDC_WD40EFRX-68N32N0_WD-WCC7K1JPY4YT (sdb) 512 7814037168

WDC_WDS240G2G0B-00EPW0_191957800289 (sdf) 512 468877312

WDC_WD40EFRX-68N32N0_WD-WCC7K5PKPLSS (sdc) 512 7814037168

SanDisk_Cruzer_Switch_4C530300400927121483-0:0 (sda) 512 15633408

import 0 sdb 64 3907018532 0 WDC_WD40EFRX-68N32N0_WD-WCC7K1JPY4YT

import disk0: (sdb) WDC_WD40EFRX-68N32N0_WD-WCC7K1JPY4YT size: 3907018532

import 1 sdc 64 3907018532 0 WDC_WD40EFRX-68N32N0_WD-WCC7K5PKPLSS

import disk1: (sdc) WDC_WD40EFRX-68N32N0_WD-WCC7K5PKPLSS size: 3907018532

import 2 sdd 64 1953514552 0 WDC_WD20EZRZ-00Z5HB0_WD-WMC4N0M4VXSX

import disk2: (sdd) WDC_WD20EZRZ-00Z5HB0_WD-WMC4N0M4VXSX size: 1953514552

import 3

import_slot: 3 missing

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You really have not defined the hardware that is outside of your Unraid box but I would bet that you have a single USB3 cable to an enclosure that holds a four hard drives.  It would be my guess that there a UBS hub inside of that box to handle all of those drives.  It appears (for whatever reason) that that hub is not able to handle four drives successfully when used in this application.  (USB hubs have never had the greatest reputation for being bulletproof...)  

28 minutes ago, QuantumMechanic said:

could that be why it falls out of the array on reboot?

Is this another problem?  What is falling out--  the boot drive or the hard drive?

 

There is one remote possibility--  That 4TB Seagate's drive motor may have problems getting the drive up to speed so that it comes online while the BIOS is looking for it.  It could also be an issue if the +12V supply can't supply all the current required during the initial spinup.  (In the back of my mind, I seem to recall that Barracudas are a bit power hungary.) 

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3 minutes ago, Frank1940 said:

1) You really have not defined the hardware that is outside of your Unraid box but I would bet that you have a single USB3 cable to an enclosure that holds a four hard drives...

2) It appears (for whatever reason) that that hub is not able to handle four drives successfully when used in this application.


3) What is falling out--  the boot drive or the hard drive?

 

4) That 4TB Seagate's drive motor may have problems getting the drive up to speed so that it comes online while the BIOS is looking for it.  It could also be an issue if the +12V supply can't supply all the current required during the initial spinup.  (In the back of my mind, I seem to recall that Barracudas are a bit power hungary.) 

1) Correct, it's a USB 3.1 Gen 2 link to a four-drive enclosure.

2) Once the array rebuilds it has zero issue, including accessing data from all four drives simultaneously through a share (I tested this early on.) The only issue is on reboot after power down.

 

3) The Seagate hard drive is coming out of the array on reboot.

 

4) The enclosure has dedicated power so I don't think this is likely, but I'm happy to entertain it. Would that still be the case given the chunk of syslog I posted that shows it in the Device Inventory on boot, though? It doesn't seem to have a problem with the drive existing, just whether it should be part of the array.

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At this point, I am stumped.  I would like to suggest that you  post up the Diagnostics file.    Tools   >>>   Diagnostics  

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It is worth pointing out that Unraid cannot handle a drive that momentarily disconnects and then re-appears with a different /dev/sdX type identifier (as can easily happen with USB drives).  Unraid expects a drive to always keep the same Id at the Linux level once it has been assigned during the boot process.   If the Id changes then Unraid treats it as a new drive.

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3 hours ago, Frank1940 said:

At this point, I am stumped.  I would like to suggest that you  post up the Diagnostics file.    Tools   >>>   Diagnostics  

Attached to this post and will edit into OP.

2 hours ago, itimpi said:

It is worth pointing out that Unraid cannot handle a drive that momentarily disconnects and then re-appears with a different /dev/sdX type identifier (as can easily happen with USB drives).  Unraid expects a drive to always keep the same Id at the Linux level once it has been assigned during the boot process.   If the Id changes then Unraid treats it as a new drive.

I've never seen that particular drive have any type identifier other than sde. I also need to mention again that once the drive has been re-integrated into the array it doesn't show any further problems. It doesn't drop out or leave the array mid-operation. I've also just tested it by taking the newly-synced array offline and restarting it, and it doesn't have an issue with that either. This problem is solely at boot-up.

 

I've attached an updated syslog from after the array restart.

montpellier-diagnostics-20190714-2211.zip montpellier-syslog-20190714-2218.zip

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TESTING EDIT: I rebooted (rather than powered down) the server and it didn't have an issue finding the drive. I'll test a power down again later on.

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