Multiple Disk failure...

[gideva]

I had some problems connected to cable so I decided to change them all and guess... 1 was faulty and 4 drives got burned!!!

I have a 2 Parity Array configuration... How many disks can I recover?

Thanks for the help

[JorgeB]

36 minutes ago, gideva said:

How many disks can I recover?

All non parity disks that are still working.

[gideva]

Sorry... I explained myself really bad.... I was talking about the data in the burned disks (disks are all gone and not working anymore unfortunately)...

[JorgeB]

9 minutes ago, gideva said:

I was talking about the data in the burned disks (disks are all gone and not working anymore unfortunately)...

Dual parity can't help with more that 2 missing missing disks, since you have 4 nothing you can do with Unraid except keep the data from the remaining data disks, if there are any.

[gideva]

Ok 2 better than nothing... To recover data is the same procedure used to recover 1 faulty disk correct? Shall I do it both at the same time or one after the other?

[itimpi]

Just now, gideva said:

Ok 2 better than nothing... To recover data is the same procedure used to recover 1 faulty disk correct? Shall I do it both at the same time or one after the other?

No.  The normal recovery process relies only works if there are less damaged disks than you have parity disks.

 

In such a case you simply use the New Config tool and assign the undamaged disks and then rebuild parity based on the new disk set. 

Make sure you do not accidentally assign a data disk to parity as you would lose the content if you did so.

[gideva]

Do you mind to guide me through this? I already lost 22TB of data and I would love to stop this disaster here...

I am preclearing disks now (guess that will take other 2/3 days for that) and than I will be ready for the "operation".

But I really feel I need some advices for that because I am afraid to make a mess!

Thanks in advance for your patience and help

[JorgeB]

Just need to go to Tools -> New config -> Keep all -> apply

 

Start array with remaining data disks and all data there should be accessible, it there's parity assigned a parity sync will begin.

[itimpi]

6 hours ago, gideva said:

Do you mind to guide me through this? I already lost 22TB of data and I would love to stop this disaster here...

I am preclearing disks now (guess that will take other 2/3 days for that) and than I will be ready for the "operation".

But I really feel I need some advices for that because I am afraid to make a mess!

Thanks in advance for your patience and help

 

There is a reasonably comprehensive write-up here in the online documentation.

[gideva]

I am almost done with the Preclear process.... And I am preparing to install the new drives (3 x 8Tb WD Red) to replace the burned ones...

I went through the on-line guide but still things are not too clear for me:

 

Since I lost 4 disks due to a faulty cable that apparently burned them (the are totally dead and unusable in any way) now I would like to rebuilt at least the 2 disks that are still considered missing by the system (the other two are not even mentioned anymore in the Array Device list). I case the disk was I would have followed the standard procedure but but multiple disk failure I am really not sure on how to proceed

 

 

According to your instruction in order to recover some of the data I shall use New Config Tool and I went through the guide itimpi suggested me but reading the first lines I am scared I will make a mess... the guide says in the very first lines the following:

 

 This tool is not part of the standard process for recovering from a disk failure... it will have the opposite effect and stop you being able to recover the contents of a failed disk intact;

 

Now my main question... should I go ahead anyway with this?

 

Sorry again if I am a pain but I guess that 20 Tb of data lost in a month are enough...

 

 

 

[trurl]

On 12/18/2022 at 6:41 AM, gideva said:

I had some problems connected to cable so I decided to change them all and guess... 1 was faulty and 4 drives got burned!!!

Do you mean the drives were fried by cable connections? Modular PSU cables are not interchangeable and many people have fried drives by trying to use modular PSU cables that aren't compatible.

 

Some people have had success recovering data from fried drives by replacing the circuit board with one from the same drive model.

[trurl]

5 hours ago, gideva said:

I would like to rebuilt at least the 2 disks that are still considered missing by the system

You can't rebuild from parity without all the disks. Parity by itself can recover nothing. Single parity will let you recover a single data disk but only if all the other disks are present. Dual parity will let you recover 2 data disks but only if all other disks are present.

 

Parity is not a substitute for backup and parity contains none of your data.

 

See this wiki for a better understanding of how parity works with all other disks:

 

https://wiki.unraid.net/Manual/Overview#Parity-Protected_Array

 

The point of New Config in your case isn't to recover anything, it is simply to get the rest of the disks into a new array and rebuild parity.

[gideva]

Ok that is clear... so if I just install 2 new disks on slot nr 3 and 9 I will be not able to recover anithing correct?

 

[JorgeB]

Correct, not from the missing disks, you need to do a new config.

[gideva]

Ok... all is working now!

 

I was able to get back one of the burned disks (I changed the circuit board as suggested by trurl) and now looks like is back working.

Now I need to understand if there is a way to put it back or if I can retreive the data from it... How sholud I proceed?

 

thanks once a gain for the help

[JorgeB]

See if you can mount them with the UD plugin.

[gideva]

I will as soon back home…

Will I be va able to access the files that are in the disks through UD?

 

[JorgeB]

Yes.

[gideva]

Great. Thanks

[gideva]

Just got home... now one of the disks is recognized by UD but I cannot mount it (the MOUNT option is grayed out and not selectable)

Any idea?

I tried to add it to the array but obviously is thelling me that it will be formatted and all data overwritten

 

[trurl]

49 minutes ago, gideva said:

add it to the array but obviously is thelling me that it will be formatted and all data overwritten

If you add it to an array that already has valid parity, it will be cleared, which is even worse than being formatted if you hope to recover any data from it.

 

Attach diagnostics to your NEXT post in this thread

[gideva]

Here is the diagnostic

 

 

monstruo-diagnostics-20221227-1843.zip

[JorgeB]

Post the output of

fdisk -l /dev/sdx

 

[gideva]

root@Monstruo:~# fdisk -l /dev/sdx
The backup GPT table is not on the end of the device.
Disk /dev/sdx: 3.64 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: WDC WD40EZRZ-00W
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 3B1388DB-2DE5-4EE0-9610-618966CC50A5

Device     Start        End    Sectors  Size Type
/dev/sdx1     64 7814037134 7814037071  3.6T Linux filesystem
root@Monstruo:~# 

[JorgeB]

Now the output of

xfs_repair -n /dev/sdx1

Note the 1 in the end.