Re: Slow disk reads - exception Emask 0x0 SAct 0x6b0000 SErr 0x0 action 0x0

["Alexander V. Makartsev" <avbetev@gmail.com>]

On 24.12.2021 20:31, rhkramer@gmail.com wrote:

> ...
> /dev/sdb is an HDD (which holds my "user data").
>
> Should I be worried?
>
> root@s19:~# smartctl -A /dev/sdb | grep -E '5 Realloc|183 Runtime|197                                  
> Current|199 UDMA'                                                                                      
>   5 Reallocated_Sector_Ct   0x0032   100   100   000    Old_age   Always       
> -       12              
> root@s19:~#  
>
>     
    Attribute #5 shows if the drive in question ever encountered and
    successfully remapped a 'bad block'. In your case it happened at
    least 12 times.
    They could've happen a few years ago, drive's firmware recovered
    from them and it was working fine ever since¹.
    But they also could've happen recently within a few days and in that
    case the drive is failing and should be replaced ASAP.
    
    For future investigation you should see full output of:
        # smartctl -A /dev/sdb
    
    And also SMART logs, to see when was last media error encountered:
        # smartctl -l error /dev/sda
    
    For now one thing is certain, your HDD had media errors, is not
    reliable² and you should have a good backup of data from it.
    It's good idea to configure 'smartd' on all hosts to monitor health
    state of your drives and notify you by mail if something happened.
    
    
    ¹ I have a 320GB HDD for a five years with, I think, contaminated
    platter. When it tries to read from some LBA range it fails with
    media errors, but if I request to read past that LBA range it works
    fine.
    As a workaround, I've repartitioned it effectively cutting off that
    faulty LBA range (around 50GB) and use it as a portable drive to
    carry some not important data and to store additional backup copies.
    I always expect it to die, but it still works fine to this day.
    
    ² Any hardware, despite being new or old, could fail at any time.
    Always expect failure and have a good backup.
-- 
With kindest regards, Alexander.

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