nanog mailing list archives

Re: Amazon diagnosis


From: Jay Ashworth <jra () baylink com>
Date: Fri, 6 May 2011 10:42:13 -0400 (EDT)

----- Original Message -----
From: "Ryan Malayter" <malayter () gmail com>

On May 5, 3:51 pm, Jay Ashworth <j... () baylink com> wrote:
----- Original Message -----
From: "Ryan Malayter" <malay... () gmail com>
I like to bag on my developers for not knowing anything about the
infrastructure, but sometimes you just can't do it right because
of
physics. Or you can't do it right without writing your own OS,
networking stacks, file systems, etc., which means it is
essentially
"impossible" in the real world.

"Physics"?

Isn't that an entirely inadequate substitute for "desire"?

Not really. For some applications, it is physics:

You misinterpreted me.  I was making fun of people who think "I want
it, and therefore it WILL be so" trumps physics, of whom there are
altogether too many in positions of power these days to suit me.

I don't have inside knowledge, but I suspect this is why Wall Street
firms have DR sites across the river in New Jersey, rather than
somewhere "safer".

You don't need inside knowledge; that issue's the subject of much
general press lately; that's exactly why they do it.

And they think it's good enough.

I truly wish that their finding out it's not wouldn't be so massively
disrupting for the rest of us poor slobs...
 
Amazon's EBS service is network-based block storage, with semantics
similar to the financial account scenario: data writes to the volume
must happen in-order at all replicas. Which is why EBS volumes cannot
have a replica a great distance away from the primary. So any
application which used the EBS abstraction for keeping consistent
state were screwed during this Amazon outage. The fact that Amazon's
availability zones were not, in fact, very isolated from each other
for this particular failure scenario compounded the problem.

Oh, so maybe "letting someone else do the cloud for you"'s a bad idea?

Whod'a thunk *that*?  :-)

Cheers,
-- jra


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