I am going to refer you to this discussion I had with the MS guys at the SQL Azure forum. I asked the very same question, and that is what they had to say in reply: Unlimited scaling at no extra cost! I was pretty surprised myself. However, off the top of my head, I can’t remember links to such references elsewhere. I’ll have to scour the SQL Azure documentation again.

As far as DB settings go, I partially agree with you. Yes, of course you’d want to relieve yourself of the burden of tuning a DB. And that is a major advantage of cloud-based DBaaS. You also have to agree that the scalability offered could be quite a motivation for using DBaaS. But a certain section of power-users and performance enthusiasts (aka, the geeks, if you may) would hate to relinquish that control in lieu of having their DBs run in high performance environments such as cloud.

If I understand this correctly, under the hood I’ll get super-performant virtual machine, which will handle all my sql queries, say, even 10 thousands per second.
The only thing I pay for is increased traffic?

If this is true, it would be awesome. Can you provide me some resources on this please?
Traffic usually gets lower at night, and no matter how strong Amazon RDS server I choose, it is still one and only one server, and without replication, isn’t able to handle high concurency sites (some smaller one requires say 10 DB HW servers).

I am willing to pay whatever the cost for SQL Azure, if they promise me parallel queries and super-efficient DB engine. But I don’t know if that is the case, because they were saying that to increase query parallelism you need to scale out (sharding). But I’m scaling out because of DB size limit, I don’t want to scale out because of their system is weak. Please, elaborate.

In that case, Amazon wins, as I can buy more powerful server than what AZURE SQL provides as their “top maximum”.

2nd thing, I think changing DB settings is against databases in the cloud. Question is, why would I like to put my DB to cloud? Answer is, because of maintance.
If I need to check it, set it up, and do various other things, I can do it on my dedicated host as well!

Thanks

@Alex:
Thanks for your valuable insight! Of course, I do realize that SQL Azure is not even out of beta yet, and yes, I’m definitely looking forward to what Microsoft has to offer in the future. But, very frankly, I really wanted to concentrate on the “now” instead of speculating. So I went ahead and compared the CTP version of SQL Azure with Amazon RDS. Justification: Take into consideration Amazon RDS’s release announcement… I knew at that point that SQL Azure was in the making, but I had no idea that Amazon was up to anything like it. Not everybody is waiting around for somebody else. And not to mention, this post will be outdated within a couple of months, I’m sure!

Subset of TSQL – yes, but the differences are very small and would affect less than 2% of development. Most of the features that are unavailable in T-SQL relate to being on a “shared” instance of SQL Server and are not available for obvious security reasons.

Agree with LAMP vs. MS Shop analogy for now, but even PHP developers can take advantage of Azure right now. The connectivity will only grow.

Just remember – Azure is only coming out of beta in Q1 of 2010. There’s a lot in the pipeline that will make a lot of your comments moot within the next year.