Re: [gentoo-user] Re: Suggestions for backup scheme?

[Rich Freeman <rich0@gentoo.org>]

On Wed, Jan 31, 2024 at 1:42 PM Wols Lists <antlists@youngman.org.uk> wrote:
>
> On 31/01/2024 17:56, Rich Freeman wrote:
> > I don't think there are
> > any RAID implementations that do full write journaling to protect
> > against the write hole problem, but those would obviously underperform
> > zfs as well.
>
> This feature has been added to mdraid, iirc.
>

Oh, it looks like it has.  Kind of annoying that it only works for a
separate device.  I guess you could create a separate partition on all
of the devices, create a mirror across all of those, and then use that
as the journal for the real raid.  It would be nice if it had an
option for an internal journal.

I'd expect the performance of btrfs/zfs to be better of course because
it just does the write to known-unused blocks, so interrupted writes
don't cause any issues.  Depending on how far it gets when interrupted
the write will be ignored (it is just data written into unused space),
or will get completed (the root of the metadata was updated and now
points to a consistent new state).

-- 
Rich