Il 2021-06-04 15:08 Eric Robinson ha scritto:
Those are all good points. Since the three legs of the information
security triad are confidentiality, integrity, and availability, this
is ultimately a security issue. We all know that information security
is not about eliminating all possible risks, as that is an
unattainable goal. It is about mitigating risks to acceptable levels.
So I guess it boils down to how each person evaluates the risks in
their own environment. Over my 38-year career, and especially the past
15 years of using Linux HA, I've seen more filesystem-type issues than
the other possible issues you mentioned, so that one tends to feature
more prominently on my risk radar.
For the very limited goal of protecting from filesystem corruptions, you
can use a snapshot/CoW layer as thinlvm. Keep multiple rolling snapshots
and you can recover from sudden filesystem corruption. However this is
simply move the SPOF down to the CoW layer (thinlvm, which is quite
complex by itself and can be considered a stripped-down
filesystem/allocator) or up to the application layer (where corruptions
are relatively quite common).
That said, nowadays a mature filesystem as EXT4 and XFS can be corrupted
(barring obscure bugs) only by:
- a double mount from different machines;
- a direct write to the underlying raw disks;
- a serious hardware issue.
For what it is worth I am now accustomed to ZFS strong data integrity
guarantee, but I fully realize that this does *not* protect from any
corruptions scenario by itself, not even on
XFS-over-ZVOL-over-DRBD-over-ZFS setups. If anything, a more complex
filesystem (and I/O setup) has *greater* chances of exposing uncommon
bugs.
So: I strongly advise on placing your filesystem over a snapshot layer,
but do not expect this to shield from any storage related issue.
Regards.
--
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.da...@assyoma.it - i...@assyoma.it
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