[quoted text, click to view] On May 25, 3:21 pm, Spam Catcher <spamhoney...@rogers.com> wrote:
> Hi all,
>
> We're in the process of investigating several HA solutions for SQL
> Server. We currently run a small database (couple GBs) but needs to be
> available for 99.99% of the time. We can tolerate some downtime... but
> preferably none.
>
> A coworker suggested we take a look at Double-Take due to the simplicity
> of installation. It seems to do what we need (replicate a database and
> have failover support) but there are a couple points that worry me:
>
> 1. It's done at the file system level
> 2. There is a delay with failover
>
> So my questions are:
>
> 1. Is SQL Server replication the way to go or clustering? Or a 3rd party
> product?
> 2. Are file system mirroring software effective in maintaining a HA
> environment - especially for SQL Server?
> 3. With SQL replciation/database mirroring/clsutering ... if a node
> fails, will we have to have handle the failure - or will the transition
> to the new node be seemless?
> 4. I briefly looked into replication in SQL Server 2000 but it looked
> like a pain to setup - any better in 2005?
>
> If we go with the built in SQL Server tools any suggestions if we should
> use Clustering vs. Replication? We like to maximum resource usage, while
> maintaining a reliable environment but would also like to keep costs
> down. As I understand... Clustering requires a shared disk - and perhaps
> that could be another point of failure?
>
> Eventually we will have remote hot stand by sites around North America
> ...
>
> Lastly - my boss gets e-mails from companies likePolyserve, etc selling
> 3rd party replication products. Should we even look into these, or will
> the built in tool in SQL Server 2000/2005 be sufficient?
It sounds like you are looking for local HA now, and then eventually
want to have the ability to do DR to your remote hot sites. In that
case, you are looking for a combination of HA and DR. You are correct
that DoubleTake is not as robust as other clustering solutions because
all they do is simply monitor system availability. The do no
application (SQL) level monitoring. So a failover would not occur if
the server was available, but SQL stopped responding. The company I
work for, SteelEye Technology, has a similar data replication
solution, but addresses some of the limitations of Double ake.
You can find more information at
http://www.steeleye.com/products/sqlserver.html If you want to contact me directly, I'd be glad to discuss in detail
all of the options available from Microsoft including, MSCS, Database
Mirroring and transactional replication.
David A. Bermingham, MCSE, MCSA:Messaging
Director of Product Management
www.steeleye.com
