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On 09/23/2014 05:13 AM, Clint Byrum wrote:
> Excerpts from Joe Gordon's message of 2014-09-22 19:04:03 -0700:

[snip]

>>
>> To me this is less about valid or invalid choices. The Zaqar team is
>> comparing Zaqar to SQS, but after digging into the two of them, zaqar
>> barely looks like SQS. Zaqar doesn't guarantee what IMHO is the most
>> important parts of SQS: the message will be delivered and will never be
>> lost by SQS. Zaqar doesn't have the same scaling properties as SQS. Zaqar
>> is aiming for low latency per message, SQS doesn't appear to be. So if
>> Zaqar isn't SQS what is Zaqar and why should I use it?
>>
> 
> I have to agree. I'd like to see a simple, non-ordered, high latency,
> high scale messaging service that can be used cheaply by cloud operators
> and users. What I see instead is a very powerful, ordered, low latency,
> medium scale messaging service that will likely cost a lot to scale out
> to the thousands of users level.

I don't fully agree :D

Let me break the above down into several points:

* Zaqar team is comparing Zaqar to SQS: True, we're comparing to the
*type* of service SQS is but not *all* the guarantees it gives. We're
not working on an exact copy of the service but on a service capable of
addressing the same use cases.

* Zaqar is not guaranteeing reliability: This is not true. Yes, the
current default write concern for the mongodb driver is `acknowledge`
but that's a bug, not a feature [0] ;)

* Zaqar doesn't have the same scaling properties as SQS: What are SQS
scaling properties? We know they have a big user base, we know they have
lots of connections, queues and what not but we don't have numbers to
compare ourselves with.

* Zaqar is aiming for low latency per message: This is not true and I'd
be curious to know where did this come from. A couple of things to consider:

	- First and foremost, low latency is a very relative measure  and it
depends on each use-case.
	- The benchmarks Kurt did were purely informative. I believe it's good
to do them every once in a while but this doesn't mean the team is
mainly focused on that.
	- Not being focused on 'low-latency' does not mean the team will
overlook performance.

* Zaqar has FIFO and SQS doesn't: FIFO won't hurt *your use-case* if
ordering is not a requirement but the lack of it does when ordering is a
must.

* Scaling out Zaqar will cost a lot: In terms of what? I'm pretty sure
it's not for free but I'd like to understand better this point and
figure out a way to improve it, if possible.

* If Zaqar isn't SQS then what is it? Why should I use it?: I don't
believe Zaqar is SQS as I don't believe nova is EC2. Do they share
similar features and provide similar services? Yes, does that mean you
can address similar use cases, hence a similar users? Yes.

In addition to the above, I believe Zaqar is a simple service, easy to
install and to interact with. From a user perspective the semantics are
few and the concepts are neither new nor difficult to grasp. From an
operators perspective, I don't believe it adds tons of complexity. It
does require the operator to deploy a replicated storage environment but
I believe all services require that.

Cheers,
Flavio

P.S: Sorry for my late answer or lack of it. I lost *all* my emails
yesterday and I'm working on recovering them.

[0] https://bugs.launchpad.net/zaqar/+bug/1372335

-- 
@flaper87
Flavio Percoco