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Oracle has had multi-homed master-master RDBMS setups for > 10 years. I'm pretty sure a half-competent Oracle administrator wouldn't be really 'surprised af' at

Oracle has had multi-homed master-master RDBMS setups for > 10 years. I'm pretty sure a half-competent Oracle administrator wouldn't be really 'surprised af' at functionality that's been in Oracle for at least a decade. For things that need 'care', this has been a solved problem for decades. Banks[0] homed in the WTC on Sept 11 kept on running because OpenVMS has had NUMA clusters and multi-node replication since the DEC Alpha days. This is with 100% transactional integrity maintained and DC failovers measured within the order of 500ms to 5s. (Obviously banks don't all run on VMS.) Platforms exist like IBM z systems let you live upgrade zOS in a test environment hosted within the mainframe to see if anything breaks, in complete isolation from production of course, revert snapshots, and do basically everything the whole ESX suite (from things like live migrations of VMotion, to newer stuff like growing raid arrays transparently / virtual storage solutions where you can add FC storage dynamically and transparently to the end user). Their stock systems let you live upgrade entire mainframes without a blip. They're built to withstand total system failure (i.e. literally processors, RAM, NICs, and PSU's could all fail on one z13 and you'd have fail-over to a hot-backup without losing any clients attached to the server). HP's Non-Stop, with which I have no experience, offers a similar comprehensive set of solutions. [0] On Sept 11, a bunch of servers went down with those buildings. * “Because of the intense heat in our data center, all systems crashed except for our AlphaServer GS160... OpenVMS wide-area clustering and volume-shadowing technology kept our primary system running off the drives at our remote site 30 miles away.” --Werner Boensch, Executive Vice President Commerzbank, North America* http://ttk.mirrors.pdp-11.ru/_vax/ftp.hp.com/openvms/integrity/OPENVMS83PRESENTATION.PDF http://ttk.mirrors.pdp-11.ru/_vax/ftp.hp.com/openvms/integri...

felixgallo 10y ago
I'm saying that an arbitrary number of exact replicas of a master can magically appear on the network believing they are the one true master, identifying themselves as such, and expecting to act that way. Additionally, an arbitrary number of database masters expecting to participate in the cluster may show up or leave at any time. That is somewhat nontrivial for even modern databases to deal with.
- bmurphy1976 10y ago
  Why run your database inside kubernetes though? We've always white gloved our database (and a few other special services). You don't have to put 100% of your infrastructure in docker/kubernetes.
  - finnh 10y ago
    That's felixgallo's point exactly.
- mentat 10y ago
  If you're running multiple copies of anything that cares about the concept of a master it better have its own consensus algorithm. Luckily such things exist and are open source.

felixgallo 10y ago

I'm saying that an arbitrary number of exact replicas of a master can magically appear on the network believing they are the one true master, identifying themselves as such, and expecting to act that way. Additionally, an arbitrary number of database masters expecting to participate in the cluster may show up or leave at any time. That is somewhat nontrivial for even modern databases to deal with.

bmurphy1976 10y ago
Why run your database inside kubernetes though? We've always white gloved our database (and a few other special services). You don't have to put 100% of your infrastructure in docker/kubernetes.
- finnh 10y ago
  That's felixgallo's point exactly.
mentat 10y ago
If you're running multiple copies of anything that cares about the concept of a master it better have its own consensus algorithm. Luckily such things exist and are open source.