Identical Serial Numbers and the Missing Disc

Backslash Backslash · 4. Oktober 2017

Could identical Serial Numbers cause my disc to go Missing?

My NAS has two discs. I replaced one and formatted it as ext4. "Physical Discs" showed the same Serial Number for both discs.

A day later (I can't remember whether I did a reboot) I couldn't see the new disc in Physical Discs or File Systems.

Looking at the disc using Linux Reader in Windows it showed as "unallocated". I changed the file system to NTFS (took less than 30 seconds) and I could immediately move a file on to it. I put it back in the NAS and mounted it as NTFS, and I could see the Windows file on it. It still had the identical Serial Number as the sister disc.

I would like to avoid the disc disappearing again so I have not changed it back to ext4 and reloaded the 1Tb of data on to it. Before I do so I am likely to have a recurrence of the problem or can I safely go ahead? blkid below.

Thanks.

Code

/dev/mmcblk0p1: SEC_TYPE="msdos" LABEL="boot" UUID="7D5C-A285" TYPE="vfat" PARTU                                                                      UID="000b5098-01"
/dev/mmcblk0p2: LABEL="omv" UUID="5d18be51-3217-4679-9c72-a54e0fc53d6b" TYPE="ex                                                                      t4" PARTUUID="000b5098-02"
/dev/mmcblk0p3: UUID="fa36508a-b3c4-4499-b30a-711dd5994225" TYPE="ext4" PARTUUID                                                                      ="000b5098-03"
/dev/sda1: LABEL="Slave" UUID="7b6edb80-0de9-47c1-ba9b-114dfb249d29" TYPE="ext3"                                                                       PARTUUID="000632fe-01"
/dev/sdb2: LABEL="New Volume" UUID="8480742A80742538" TYPE="ntfs" PARTLABEL="Bas                                                                      ic data partition" PARTUUID="70d17f4b-9d2f-4f0b-a8c0-6a94f1f553bb"
/dev/mmcblk0: PTUUID="000b5098" PTTYPE="dos"
/dev/sdb1: PARTLABEL="Microsoft reserved partition" PARTUUID="973bd43f-59fc-40e3                                                                      -aae7-7c2d9a5022de"
root@ham-gat:~# blkid
/dev/mmcblk0p1: SEC_TYPE="msdos" LABEL="boot" UUID="7D5C-A285" TYPE="vfat" PARTUUID="000b5098-01"
/dev/mmcblk0p2: LABEL="omv" UUID="5d18be51-3217-4679-9c72-a54e0fc53d6b" TYPE="ext4" PARTUUID="000b5098-02"
/dev/mmcblk0p3: UUID="fa36508a-b3c4-4499-b30a-711dd5994225" TYPE="ext4" PARTUUID="000b5098-03"
/dev/sda1: LABEL="Slave" UUID="7b6edb80-0de9-47c1-ba9b-114dfb249d29" TYPE="ext3" PARTUUID="000632fe-01"
/dev/sdb2: LABEL="New Volume" UUID="8480742A80742538" TYPE="ntfs" PARTLABEL="Basic data partition" PARTUUID="70d17f4b-9d2f-4f0b-a8c0-6a94f1f553bb"
/dev/mmcblk0: PTUUID="000b5098" PTTYPE="dos"
/dev/sdb1: PARTLABEL="Microsoft reserved partition" PARTUUID="973bd43f-59fc-40e3-aae7-7c2d9a5022de"

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tkaiser · 5. Oktober 2017

Zitat von Backslash Backslash

"Physical Discs" showed the same Serial Number for both discs.

If your NAS is based on a Raspberry Pi then you're talking about USB storage and obviously USB-to-SATA bridges in your USB disk enclosure doing silly things. What's the output from

Code

armbianmonitor -u
for disk in /dev/sd* ; do smartctl -d sat -a $disk ; done

Backslash Backslash · 5. Oktober 2017

Your comment on USB-SATA cables is interesting. I don't recall whether the serial numbers were identical before I changed one of the discs - they had run happily together for more than a year. My concern is to ensure that it is not the identical serial numbers which are causing my disc to disappear and become unallocated.

Entering your proposed command I get:

Code

-bash: armbianmonitor: command not found

Meanwhile I get this with hdparm:

Code

hdparm -I /dev/sd? | grep 'Serial\ Number'
        Serial Number:      WD-WXK1A10X4320
        Serial Number:      WCC2RCP3

So the system sees the real serial numbers whilst the OMV GUI gives different serial numbers, identical for both discs (even when using different USB-SATA cables). That serial number is 116AC2101219.

As I say, my concern is to avoid a repetition of the vanishing disc. If identical GUI serial numbers are a non-issue, I'll try again with moving all of my data on to the new disc.

Incidentally, it shouldn't be a power supply problem as I run everything from a powered hub and have had previously had three cohabiting discs - I only had two discs when the new one became unallocated.

tkaiser · 5. Oktober 2017

Zitat von Backslash Backslash

armbianmonitor: command not found

Ok, old image with no built-in 'upload debug stuff' function. Too much waste of time supporting this. Anyway, if you do a web search for the serial number 116AC2101219 you get displayed and try out smartctl (as suggested) and 'lsusb -v' you might figure out why both disks get the same serial (with almost 101% probability it's the USB-to-SATA bridge IC doing something wrong) and at least I wouldn't trust in such a setup

Backslash Backslash · 6. Oktober 2017

OK, thanks. Somehow it has worked for the last year, referencing the UUIDs, so the Serial Numbers were ignored.

My biggest worry is how a disc could just go "unallocated". This is more disturbing as this disc is going to be my master back-up. I don't want it to become unallocated at some future date.

tkaiser · 6. Oktober 2017

Zitat von Backslash Backslash

Somehow it has worked for the last year, referencing the UUIDs, so the Serial Numbers were ignored.

I really don't get why you're focused on 'Serial Numbers' and not scared that your disk vanished. I would better investigate the reasons (maybe now you can still check dmesg output or contents of /var/log/syslog). But again: you're using one of the old RPi images where there's no 'armbianmonitor -u' capability and asking for every single bit of information (eg smartctl output I asked for and got some irrelevant hdparm stuff as answer) is simply too much waste of time

Backslash Backslash · 6. Oktober 2017

I am worried but I don't know what to do. I gave the output of hdparm because it shows clearly that the actual disc serial number is different from that under the OMV GUI. Can you advise what dmesg is and what I look for in /var/log/syslog?

I originally thought that the disc was at fault because it became unallocated, it lost all formatting and was unreadable. Could the OS cause this? I presumed it was a disc failure, even though the disc is new.

I'm not sure about the old image of RPi - I'm using OMV 3.0.59.

tkaiser · 6. Oktober 2017

Zitat von Backslash Backslash

I gave the output of hdparm

...since you're fascinated by the idea of mismatching serial numbers for whatever reasons. I asked for something different and that for a reason but anyway. Use a search engine wrt dmesg and syslog, post the contents in case you want someone more experienced to look into and better stop using a Raspberry Pi as NAS especially with your really old USB disk enclosures (HDDs are one part, the other is the USB-to-SATA bridge in such USB disk enclosures, then USB is a technology best described as cheap consumer crap and RPi's USB implementation is maybe the worst possible)

There are an awful lot of people using OMV on Raspberries and in the meantime I totally regret being part of the problem and not a solution

gerdescm · 20. April 2020

I'm having the exact same issue as you. I have two enclosures that are returning the same serial number on a new setup.

Any chance you got this solved?

I can see each drive if I unplug on and plug in the other, but if I plug both in only one is recognized. Presumably this is because OMV is using the drive enclosure serial rather than the actual HDD serial and can't recognized that there are two drives installed. I'm hoping you found a solution to this.

I found at least one other thread from someone with the same issue. I know this is an old thread but I'm casting a wide net since I've not been able to find a complete solution.

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