cloud4java developers – brief notes

Am an enterprise java developer, not a web developer. I feel PaaS is designed more for the web developer.

I agree with the general observation that IaaS doesn’t impact us significantly.

I feel SaaS doesn’t either. SaaS could offer devops (build/delivery) services for java developer teams.

PaaS has the biggest impact. We have to use the API /SDK provided by the PaaS vendor. Often no SQL DB. Can’t access a particular host’s file system. MOM is rarely provided.

mapReduce – rent cloud resources#IaaS

MR is popular on clouds — offered by AWS/Azure/Google.

I used to question the validity of on-demand/rent proposition. I felt during a peak period everyone is busy and in an off-peak period everyone has low volume. Now I think Hadoop is a nice example. 
It often runs for a short time but involves many compute nodes. This could be in a off-peak period. Without cloud, the Hadoop will have to make do with much fewer compute nodes.
Further, any batch job in general could be scheduled off-peak. 

cloud DB sharding – phrasebook#eg PaaS

I read quite a few books touching on sharding, but one book puts it succinctly into the big picture of noSQL, big data, web2.0 and cloud — [[cloud architecture patterns]]

PWM partition — The position database in PWM was partitioned into regions like Asia, Europe, Latam, …  This is an early example of sharding.
custom built — early sharding tends to be custom-built, like PWM. Nowadays standard sharding support is available in many databases, so no more custom-built.
noSQL and SQL databases — both support sharding
Autonomous — Shards do not depend on (or reference) each other.
Static data tables — are not sharded but replicated.