

Call me maybe: NuoDB - ceejayoz
http://aphyr.com/posts/292-call-me-maybe-nuodb

======
fry_the_guy
I think the better argument against the CAP theorem is that while it is true,
is it not really that useful. If you have a database with nodes in three data
centers, it is much more likely that one of the data centers becomes
disconnected (partitioned) from the rest of the internet, rather than that the
internet itself is partitioned. In this case, a CP system can still remain
available to the internet, it just can't also remain available to the nodes
within the disconnected data center.

[https://foundationdb.com/white-papers/the-cap-
theorem](https://foundationdb.com/white-papers/the-cap-theorem)

~~~
aphyr
Meanwhile, [http://blog.pagerduty.com/2013/04/outage-post-mortem-
april-1...](http://blog.pagerduty.com/2013/04/outage-post-mortem-
april-13-2013/)

~~~
fry_the_guy
Discussing the CAP theorem is a discussion on what is theoretically possible.

All I am claiming is that it is theoretically possible to make a CP system
that, in practice, is highly available. That does not mean one actually
exists.

~~~
aphyr
Absolutely agreed; I'm just saying that as the Pagerduty postmortem
demonstrates, CP availability becomes trickier as you increase the number of
sites--and there are unavoidable minimum latency bounds due to the speed of
light. Those bounds may be unacceptably high; this is why Google Spanner
chooses instead to enforce strong bounds on clock synchronization.

