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.
