How far can I trust Vserver ?

[Ruslan Zasukhin]

On 10/12/04 8:15 PM, "Eric Ferrer" <wonderfef at noos.fr> wrote:

Hi Eric,

You ask existed Vserver users?

Then I think you should get answers from Florian, Key Ray, others.
They ship RELEASE of their apps about year already.


> Hello all,
> 
> I've been developing a big client-server application for more than 3 years
> now using RB.
> Today, a dozen of users use this application all day long for their job
> tasks.
> 
> My number of users is going to jump up to 40 (and maybe more than that)
> because my software is going to be used in 3 new premises.
> The Server I developed is not made for so many users working simultaneously.

> So I'm now testing Vserver, which is just fine and great according to my
> first tests.
> 
> But when I read the documentation and some posts on the lists, I ask myself
> this question "How far can I trust Vserver?".

> Here are the points I'd like hear some feedback from:
> 
> € MaxClientTimeOut
> There is no reason my application would suddenly disconnect from the server.
> Is the user makes the choice not to quit the application, the application
> should not disconnect.

But what if hardware failure?
Power of hub for example ?

> This Vserver parameter sounds important to me, because the manual gives the
> example of "having a coffee", which is not very long!
> Is is dangerous to keep clients connected all day long?

No.

And note, you can set this parameter to be infinity.
As result your clients will NOT be disconnected.

 
> € Threads
> If I understood, this is the max number of clients connected simultaneously.

NO.

> The manual says that the recommended values are "5 to 20", which is too few
> for my needs.
> In another hand, I think I read somewhere that Vserver licence could be
> bought up to "unlimited connections".
> There must be something I did not understand...

No. Valentina do NOT use simple model "one user one thread"
    (mySQL use it for example).

Instead Valentina Server use quite complex model that was suggested by ACE
network framework. In short you can have 100 connected users, but 5-10
threads inside of kernel.

Reason of such model is that if you have MANY threads on single SPU or even
2-CP computer, they start work just slower.


> € Testing with many connections
> Does anyone has already tested Vserver with many many connections ?
> I'm alone and I can't simulate 20 users working on the database at the same
> time!

I believe we have own tests for this.

In fact you also can create MANY connections from single application!
This is not prohibited.

Just write loop which establish connections.
Remember although, Windows on default have limit 64 connections per process.


> € DB corruption and Vserver stability
> My application would make an intensive use of quite complex SQL SELECT
> statements, and many times some loops would be called to insert, delete or
> add records using cursors...
> Is that dangerous?

> Does the database get corrupted with the time?
> Does Vserver happen to unexpectedly quit ?

I wonder if you have use Valentina local before?

Honestly. Yes, sometimes we get crash reports from Vserver.

Yes, sometimes people report about corrupted dbs.
In the same time some developers report that they have never see any
corrupted db for years distributing tens of thousands of copies.

I will recommend you develop prototype of your task and test it intensively.


-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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