Giovanni Tessore wrote:
If you have a degraded array which gets an unrecoverable read error,
reconstruction is not feasible any more, the disk is mark failed and
the whole array fails. The you have to recreate with --force or
--assume-clean, start to backup data.. but on each other read errors
you get the array offline again ... recreate in --force mode .. and so
on (which needs skill and it's error prone).
Maybe would be useful to have unrecoverable read errors on degraded
array to:
1) sent a big alert to admin, with detailed info
2) don't fail the disk and whole array, but set it into readonly mode
3) report read errors to the OS (as for a single drive)
This would allow to do a partial backup and save as most data as
possible without having to tamper with create --force etc..
Experienced use may still try to overcome the situation readding
devices (maybe one gone out simply due to timeout), with create
--force, etc.. but many persons may have big troubles doing so, and
they just see all their data gone, when just a few sectors over many
Tb are unreadable and most data cab be saved.
I think if you set it to readonly mode, it wouldn't degrade further even
on read error.
I think I saw this from the source code, but now I'm not really sure any
more.
Do you want to check?
If what I say is correct, you can get data out relatively easily with 1
operation. The array won't go down.
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