Hi,

I'm currently looking in the possiblities for a SQL server install. The web
project needs a SQL database with a high availability. Speed and size are not
that important as the load will be medium (especially for the new enterprise
class servers), but it cannot eb offline for more then minutes. Assuming
there is suffient budget what option would be preferred:
HP DL380 cluster with SAN : diskset in SAN RAID 1+0 with SQL enterprise and
SQL virtual server setup
OR
2x Fully redundent HP DL380's with own diskset (RAID 1+0), one active SQL
Std, and one passive. Replication using DoubleTake or Neverfail alikes.
The fail-switch should also be automatic and should react within max 5
minutes.

Any idea's pro + cons?

Thanks

Have you looked at Log Shipping as an alternative?
Regards

Darryl Pollock

Squirrel Consulting

www.remotesquirrel.com - Performance Monitoring - Anytime ! Anywhere!


"christophe" <christophe (AT) discussions (DOT) microsoft.com> wrote

yes, but the data can only be out of sync for max a few minutes and from what
I read replication is faster for something like that. I also need an
automated switch to the standby server in case of a failure of the primary
server. The application only knows 1 SQL server connection.

"Darryl Pollock" wrote:

Hi

Just remember, Cluster or disk/volume replication level does not protect you
against database/disk corruption. The corruption is faithfully propogated to
the other drives in the case of replication and is on the single copy on the
SAN.

For SQL 2000, Microsoft Windows Clustering is the way for the least downtime
and no human intervention is required. Clusters typically fail over in <20
seconds, depending on how many transactions need to rolled forward/back.

Regards
Mike

"christophe" wrote:

I would argue that the time required to failover is a function of how long
it takes for the transaction log to be applied from the failed node to the
failed over node.

For most production systems with VLDBs you should be dumping the log very
frequently, ie under 5 minutes.

While 20 s is an often quoted statistic, I think 1 - 2 minutes might be more
realistic.
--
Hilary Cotter
Looking for a SQL Server replication book?
http://www.nwsu.com/0974973602.html


"Mike Epprecht (SQL MVP)" <mike (AT) epprecht (DOT) net> wrote