Re: [RFE] Please, add optional RAID1 feature (= chunk checksums) to make it more robust

it's not normal to lost data but it's possible (electronic problems,
radioactive problems or another problem not related maybe lost of disk
magnetic properties)

It might be also caused by a bug in the SATA controller driver.
And nobody can be sure that there will be no new issues in case
of future chipsets and their very first driver versions.

since we are at block device layer (md) i don't know if we
could/should implement a recovery algorithm or just a badblock report
algorithm (checksum)

Direct recovery would be better since it doesn't cost much and lowers
the possibility of data loss due to the second drive's failure.

maybe for a 'fast' solution you could use raid5 or raid6? while we
discuss if this could/should/will not be implemented?!
i think raid5/6 have checksums and others tools to get this type of
problem while you can use your normal filesystem (ext3? ext4? reiser?
xfs?) or direct the block device (a oracle database for example or
mysql innodb)

RAID5/6 would need more drives than I actually have, right? There's
not enough space for 3 drives in those small and cheap mini-ITX based home
routers/servers I started building 3 years ago. Moreover that would mean
a need for better cooling and a higher power consumption and that's
something I'm exactly trying to avoid in this particular case.

I slowly started to accept the idea, that I'll have to migrate my
systems from mdraid to btrfs if there's no solution soon :( I don't
like it much, but there's apparently nothing else I can do about that.

--
Roberto Spadim
Spadim Technology / SPAEmpresarial

Thanks a lot for your answers and have a nice day.

Regards,
Jaromir.

--
Jaromir Capik
Red Hat Czech, s.r.o.
Software Engineer / BaseOS

Email: jcapik@redhat.com
Web: www.cz.redhat.com
Red Hat Czech s.r.o., Purkynova 99/71, 612 45, Brno, Czech Republic
IC: 27690016