On: Show HN: GoScale Cloud Scaling in Milliseconds

[moe]

This happens within 2 seconds.

I'm sorry but statements like that freak me out a bit.

Do I get a warning when my instance is going to be migrated instead of resized, and an estimate of the downtime?

Because unless you found a way to defy physics you are pretty surely not migrating e.g. a 4GB Ram/40GB disk instance in anywhere close to 2 seconds.

[devopstom → moe]

Actually..

If you had all of the instance data stored on a fast SAN, so that it was available to all of the hosts simultaneously (possible.)

And you had an ultra-high speed interconnect (40Gbit Infiniband would do) between hosts, for sharing the memory state when you migrate..

4GB of memory, at 40Gbit/s would be transferred in 0.8s. (assuming perfect throughput, all cows are spherical, etc..)

[accountoftheday → devopstom]

Actually... you do not need that fast a network. You can converge state incrementally rather than transfer it in one go. Xen and VMware do this. Surely the cost of a fast SAN and interconnect would quickly outpace the (imho minor) savings from smaller memory allocations.

[devopstom → accountoftheday]

Yeah, you can do that too..