My bad: CAP = consistency, availability and partition-tolerance. Jörg
2017-01-17 19:35 GMT+01:00 Jörg Hoh <[email protected]>: > HI Lance, > > 2017-01-17 19:19 GMT+01:00 lancedolan <[email protected]>: > >> ... >> >> If "being eventual" is the reason we can't go stateless, then how is adobe >> getting away with it if we know their architecture is also eventual?? What >> am I missing? I understand that the documentation I linked is a >> distributed >> segment store architecture and mine is a share documentstore datastore, >> but >> what is the REASON for them allowing a stateless (not sticky) >> architecture, >> if the REASON is not eventual consistency ? Both architectures are >> eventual. >> >> > It depends a lot on your usecase. For example Facebook is also eventually > consistent (I sometimes think that the timeline is different on every > reload). Also the CAP theorem says, that you can choose only 2 of > "consistency, atomicity and partition-tolerance". > > In the case of independent segment stores (in Adobe speak: publish > instances, stateless loadbalancing) you have a lot of individual requests > from multiple users. So you as an individual cannot decide if another gets > the very same content as you. And as long as this eventual consistency is > not causing annoyances and friction on and end-user side (e.g. you hit a > intra-side link, which returns in a 404), I would not consider it as a > problem. And these problems occur so rarely, that many (including me and > many other users of AEM) ignore it for daily work. But this is only valid > for a readonly usecase! > > The situation is different on the clustered documentNodeStore (in Adobe > speak: authoring, sticky connections). Due to write skew write operations > will be visible with a small delay on all cluster nodes. But because there > it matters that a user sees the changes he just did. And to overcome this > limitation with the write skew, the recommendation is to use > sticky-sessions. > > > > Jörg > > > -- > Cheers, > Jörg Hoh, > > http://cqdump.wordpress.com > Twitter: @joerghoh > -- Cheers, Jörg Hoh, http://cqdump.wordpress.com Twitter: @joerghoh
