Thanks for all the replies – it is more or less as I suspected.

The shared SAN drive is very fast and provide the locking/visibility guarantees, it is designed to do so.
But we won’t be following that option anymore, it is too much of a risk for us. We have over 200 big databases with lots of r/w operations on our servers and the last corruption we experienced was 3 years ago on only one of them, so we are not ready to risk all that stability.
We will go with a normal replication procedure instead.





Atenciosamente,

Rudi Feijó


Multidados Informática Ltda.
* (11) 2579-8794 / 2579-8795
* <mailto:ariane.cutlac@...> rudi.feijo@...
* <http://www.multidadosti.com.br/> www.multidadosti.com.br
<http://www.timesheet.com.br/> www.timesheet.com.br



From: firebird-support@yahoogroups.com [mailto:firebird-support@yahoogroups.com]
Sent: quarta-feira, 16 de dezembro de 2015 17:31
To: firebird-support@yahoogroups.com
Subject: Re: [firebird-support] 2 servers acessing one database





On Wed, 16 Dec 2015 08:41:11 -0500, "DougC <mailto:doug@...> doug@...
[firebird-support]" < <mailto:firebird-support@yahoogroups.com> firebird-support@yahoogroups.com> wrote:

> No, it is not. Two firebird server instances cannot access the same
> database regardless of where it is located.

On the same physical machine it can: that is how Classic Server works.

The major problem is not only shared access to the file (although that can
give some problems), the larger problem is that the lockfiles aren't shared
across machines, which means you will be corrupting the database left and
right.

If a shared storage would provide the right locking and visibility
guarantees, and if Firebird would be able to use lockfiles on a shared
storge, it would actually work (that is - if I understood it correctly -
how one of the first Interbase versions worked). However unless access to
that shared storage is fast, performance would probably be worse than using
a single instance. And if the shared storage doesn't provide the right
locking and visibility guarantees, it will corrupt your database.

So short answer: it won't work.

Mark



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