Re: [ LR] Kernel 4.8.4: INFO: task kworker/u16:8:289 blocked for more than 120 seconds.

[TomK <tk@mdevsys.com>]

On 10/31/2016 3:29 PM, Wols Lists wrote:
> On 30/10/16 18:56, TomK wrote:
>>
>> We did not do a thorough R/W test to see how the error and bad disk
>> affected the data stored on the array but did notice pauses and
>> slowdowns on the CIFS share presented from it with pauses and generally
>> difficulty in reading data, however no data errors that we could see.
>> Since then we replaced the 2TB Seagate with a new 2TB WD and everything
>> is fine even if the array is degraded.  But as soon as we put in this
>> bad disk, it degraded to it's previous behaviour.  Yet the array didn't
>> catch it as a failed disk until the disk was nearly completely
>> inaccessible.
>
> What is this 2TB Seagate? A Barracuda? There's your problem, quite
> possibly. Sounds like you've got your timeouts correctly matched, so
> this drive is responding, but taking ages to do so. And that's why it
> doesn't get kicked, but it knackers system response times - the kernel
> is correctly configured to wait for the geriatric to respond.
>
> Cheers,
> Wol
>

Hey Wols,

It's about a 2-3 year old Seagate but not a Barracuda.  They did not 
come with high ratings back then.  I also do adjust other recommended 
settings like write caches etc.

With the previous answer provided by Andreas, I got a very good picture 
what scope of issues RAID should cover and what is not.

So rightly so there is a gap where RAID will not cover all disk failures 
while the disk may impact the applications sitting on top of the array.

Where I was going with this as well is to help me identify what other 
tools I may need in solutions that use RAID.  In this case the answer 
Andreas provided tells me I have to have specific software for disk 
monitoring to the array that would tell me potential issues ahead of 
time alongside the RAID.

On a side note, I like to see the RAID mailing lists so busy.  If I were 
to read the various blog posts, I would believe RAID died 5 years ago.  :)

-- 
Cheers,
Tom K.
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