Re: SMART-info used by mdadm/mdmon?

[Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>]

On Fri, 24 Nov 2023 10:41:37 +0000
Erik Starbäck <erik.starback@uppmax.uu.se> wrote:

> Hi!
> 
> I try to understand if mdadm/mdmon use SMART-information to realize if a disk
> is broken (or will soon be broken), or if they only use more concrete
> information about read/writes and different response times to kick out a disk
> from a mdadm-raid.

Hello Erik,
No mdadm and mdmon do not use SMART to make decision about disk in raid
array. I think that it is not a task for mdadm to do so. mdadm is a MD manager-
it cares about making requesting action possible when the problem is you asking
about it more predicting drive failure.
mdadm will complete the action requested by other utility which may be
projected to track and analyze SMARTs.

mdadm reacts on "remove" event triggered by udev so it means that device
must be removed by the device driver first.
Another way is high error rate from device - in this case MD drives kicks out
the drive itself. However it is rather sporadic and happens only on certain
conditions like high workload.

Hope it is helpful!
Mariusz
> 
> /Erik Starbäck, UPPMAX Uppsala University
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