That's a good review of EBS issues, thanks for the link. On Tue, Apr 26, 2011 at 10:41 PM, kowsik <kow...@gmail.com> wrote:
> On Tue, Apr 26, 2011 at 8:31 PM, Wes Gamble <we...@att.net> wrote: > > On 4/26/11 10:07 PM, kowsik wrote: > >> > >> On Tue, Apr 26, 2011 at 8:01 PM, Wes Gamble<we...@att.net> wrote: > >>> > >>> I would like to understand this statement from the Heroku post-mortem > >>> better: > >>> > >>> "2) Block storage is not a cloud-friendly technology. EC2, S3, and > other > >>> AWS > >>> services have grown much more stable, reliable, and performant over the > >>> four > >>> years we've been using them. EBS, unfortunately, has not improved much, > >>> and > >>> in fact has possibly gotten worse. Amazon employs some of the best > >>> infrastructure engineers in the world: if they can't make it work, then > >>> probably no one can. Block storage has physical locality that can't > >>> easily > >>> be transferred. That makes it not a cloud-friendly technology. With > this > >>> information in hand, we'll be taking a hard look on how to reduce our > >>> dependence on EBS." > >> > >> One of the comments that I've heard is that EBS is like a NAS drive, > >> except its generating traffic on the same interface as the > >> application. The more the app load that triggers more DB/file system > >> load, the higher the chances of network congestion. > >> > >> You can't access a disk drive that's sitting across a different region > >> because of the geo latency. You might be able to get away with the > >> throughput, but the latency will be very visible. This is partly why > >> an EBS in a particular AZ has to be used by an instance in that AZ. > >> > >> These are all guesses into a black box that we don't necessarily know > >> how things operate. People are guessing based on the constraints > >> presented by Amazon and the variability in performance. > > > > That makes sense. > > > > So, an entire region of AWS was down, correct? > > Again, basing on "hearsay" about the outage, when one of the AZ went > down, apparently the EBS controller/thingamagic started mirroring the > volumes to the other AZs which essentially brought down the whole > region. Or something like that. Until Amazon comes out with the > post-mortem, its anybody's guess as to what happened. > > Just read this blog: > http://stu.mp/2011/04/the-cloud-is-not-a-silver-bullet.html > > Which seemed to resonate with me. Cloud is the ultimate embodiment of > Murphy's Law. Everything bad that can happen, will happen. As long as > you are prepared for the worst, the cloud a beautiful warm place with > pixie dust and sunny skies. :) > > K. > --- > http://blitz.io > http://twitter.com/pcapr > http://labs.mudynamics.com > > -- > You received this message because you are subscribed to the Google Groups > "Heroku" group. > To post to this group, send email to heroku@googlegroups.com. > To unsubscribe from this group, send email to > heroku+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/heroku?hl=en. > > -- -John -- You received this message because you are subscribed to the Google Groups "Heroku" group. To post to this group, send email to heroku@googlegroups.com. To unsubscribe from this group, send email to heroku+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/heroku?hl=en.
