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Critical error - what to do about it?

Palomino

Neophyte
Joined
Feb 21, 2020
Messages
5
I have an alert which reads as follows -
CRITICAL
Boot pool status is ONLINE: One or more devices has experienced an error resulting in data corruption.
While this is, to some extent, helpful what device is it referring to and what is the error? If it has detected an error it would be useful to know where.
Is it possible the boot device itself is corrupted in some way? I'm using an M.2 drive as the boot drive - I did this in the expectation that it would be more reliable than a USB drive.

Other thoughts
- I have three data drives, all WD reds.
- could the the critical message above be caused by memory errors?


After booting the system "seems" to work fine.
 

Heracles

Neophyte Sage
Joined
Feb 2, 2018
Messages
676
Hey @Palomino,

What is the output of zpool status ?

Code:
root@Atlas[~]# zpool status
  pool: freenas-boot
 state: ONLINE
  scan: scrub repaired 0 in 0 days 00:01:02 with 0 errors on Sat May 30 03:46:02 2020
config:

        NAME        STATE     READ WRITE CKSUM
        freenas-boot  ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            da8p2   ONLINE       0     0     0
            da9p2   ONLINE       0     0     0

errors: No known data errors
root@Atlas[~]#


So Yes, it looks like your boot drive is experiencing some problems. You say your server is up and running as of now. Take a backup of your config right now in case you need to re-install your boot device. Also, if your pool is encrypted, be sure you have all the keys required to decrypt it.
 

Palomino

Neophyte
Joined
Feb 21, 2020
Messages
5
Thank you for your response.

Here's the zpool status as requested. This doesn't look good.
pool: freenas-boot
state: ONLINE
status: One or more devices has experienced an error resulting in data
corruption. Applications may be affected.
action: Restore the file in question if possible. Otherwise restore the
entire pool from backup.
see: http://illumos.org/msg/ZFS-8000-8A
scan: scrub repaired 0 in 0 days 00:00:06 with 64 errors on Fri Jun 5 03:45:06 2020
config:
(The data drives all have zero errors so I haven't listed them above.)

I also ran this with the verbose option but haven't included the [long] list of files. I can do this if it would be helpful.

I have backed up the configuration in System-General.
The file name is "NAS03-FreeNAS-11.3-U3.1-20200607085455.tar" which I have saved on my PC. NAS03 is the server name.

Given my limited understanding of how this works I plan to carry out the following -
1. Create a fresh, new boot disk on a fresh, new USB drive.
2. Boot from that drive.
3. Restore the configuration file [that I backed up above] using the option in System-General.
4. Cross my fingers.
5. Check the system now looks like it should.
 

Heracles

Neophyte Sage
Joined
Feb 2, 2018
Messages
676
Hey @Palomino

Given my limited understanding of how this works I plan to carry out the following -
1. Create a fresh, new boot disk on a fresh, new USB drive.
2. Boot from that drive.
3. Restore the configuration file [that I backed up above] using the option in System-General.
4. Cross my fingers.
5. Check the system now looks like it should.
I confirm you that this is the proper way to do it, if the pool is not encrypted. If you encrypted your pool, there are extra steps to take. If you did not encrypt it (and really, you should not encrypt your pool), then your procedure is the right one.

What you can also do is to mirror your boot drive. For that, pick 2 identical USB drives and during the install, select both of them. The installer will create a mirror with them by itself. In that case, should the same happen, you will have redundancy to survive better.

Good luck with that,
 

Palomino

Neophyte
Joined
Feb 21, 2020
Messages
5
Thank you for your advice.
I can confirm my pool is not encrypted.

A quick question to finish : If I use mirrored boot drives I can only set one of them as the boot drive in the BIOS. How then does FreeNAS keep the two drives in sync? If one drive fails presumably the other will boot normally on its own?
 
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