Re: [ANNOUNCE] Ramback: faster than a speeding bullet

[Ric Wheeler <ric@emc.com>]

Lars Marowsky-Bree wrote:
> On 2008-03-11T03:50:18, Daniel Phillips <phillips@phunq.net> wrote:
> 
>>> as well. In fact, the most common reason for unorderly shutdowns are
>>> kernel crashes, not power failures in my experience.
>> What are you doing to your kernel?
> 
> I guess I'm being really vicious to them: I expose it to customers and
> the real world.
> 
> My own servers also have uptimes of >400 days sometimes, and I wonder
> what customers do to the poor things.
> 
> And yes, I'm not saying I don't see your point for specialised
> deployments (filesystems which are easy to rebuild from scratch), but
> transactional integrity is a requirement I'd rank really high on the
> desirable list of features if I was you.
> 
>>> So "perfectly reliable if UPS power does not fail" seems a bit over the
>>> top.
>> It works for EMC :-)
> 
> Where they control the hardware and run a rather specialized OS as well,
> not a general purpose system like Linux on "commodity" hardware ;-)

Actually, in Centera we use generic hardware with a fairly normal kernel 
which has strategic backports from upstream (libata, nic drivers, etc).

No UPS in the picture.  Data integrity is protected by working with the 
application team to insure they understand when data is safely on the 
disk platter and working with IO & FS people to try and make sure we 
don't lie to them (too much ) about that promise.

The centera boxes are tested with power failure & error injection and by 
all of our customers in all those ways customers do ;-)

ric