[linux-lvm] Powerfailure and snapshot consistency

[Les Mikesell]

On 3/26/2011 11:07 AM, Stuart D. Gathman wrote:
>
> It is not a bug. Some progress can be made with barriers (similar to
> fsync())
> that block until all affected blocks are confirmed written on all devices
> through all levels of the storage stack (e.g. written to all legs
> of a raid1 device). My database does an fsync after each journal batch,
> and I think it reasonable to hope that this guarantees that the writes
> from the journal batch complete before any subsequent writes. I don't
> depend on any other ordering.

Is there some non-destructive diagnostic that can tell you if a running 
machine can or can't manage write ordering correctly through all of its 
software and hardware layers?

-- 
   Les Mikesell
    lesmikesell at gmail.com