November 7, 2002 at 7:39 am
I am new to Windows/SQL Clustering and I want to make sure I understand how running two SQL instances work in each case.
Active/Passive two node setup. Two instances on one node using all the processing and memory power of that one node and the other node 'sleeping' waiting for failover.
Active/Active two node setup. One instance on each node (ie prod/report) and prod will failover to report if something happens to the node running the prod instance. Thats of course if its setup correctly.
Am I right on this?
November 7, 2002 at 8:52 am
If you are talking instances then you are still talking active passive. You have to consider an instance as a seperate server (especially with licensing).
So if you have 2 servers each with one instance on them and you have 2 databases.
If you have one database active on one server and one on the other server then you have active/active. In this situation if server1 fails the database is brought up on the other server.
If you have both databases on one server and then if it fails then the databases are brought up on the other server. The second server is not being used until the first fails. This is Active/Passive.
Active/Active gives best performance and costs more (2 sets of licenses).
So basically you need to license any instance that is being used. These are active. If you have an instance that is just sitting there waiting to be used in the event of a failure then it is passive and so does not need to be licensed.
I hope that helps
Simon Sabin
Co-author of SQL Server 2000 XML Distilled
http://www.amazon.co.uk/exec/obidos/ASIN/1904347088
Simon Sabin
SQL Server MVP
http://sqlblogcasts.com/blogs/simons
November 7, 2002 at 8:56 am
Not exactly. Active/Active is right. But Active/Passive is nomenclature typically used for only one instance.
Active/Passive:
- Only one instance of SQL Server.
- Runs on one node (active).
- Other node is for failover (passive).
Active/Active:
- Two instances.
- First instance (usually default) runs on one node (active).
- Second node is typically used for failover for first instance.
- Second instance (has to be a named instance) typically runs on the second node (also called active).
- First node typically used for failover for second instance.
- You run an instance on each node is to maximize memory and processor resources for each instance.
- One node can (and in the event of one of the nodes being down) run both instances.
K. Brian Kelley
http://www.truthsolutions.com/
Author: Start to Finish Guide to SQL Server Performance Monitoring
http://www.netimpress.com/shop/product.asp?ProductID=NI-SQL1
K. Brian Kelley
@kbriankelley
November 7, 2002 at 10:09 am
Having spent some time looking into setting up an Active/Passive cluster I agree with the comments made by bkelley.
Am I also right in thinking that Active/Passive is normally used to provide solely fault tolerence where as Active/Active can provide increased performance in addition to fault tolerance by each of the active nodes being part of a federated database?
Edited by - paulhumphris on 11/07/2002 10:15:36 AM
November 7, 2002 at 2:53 pm
Based on a profile workload trace for Disk and Processor IO, we saw a 37% gain in performance by going to active/active clustering with federated servers in our production enviroment. I certianly wouldn't say that everyone would gain as much (or perhaps as little) but it is what we got.
November 7, 2002 at 3:35 pm
You can use federated databases, but that's not the usual reason for an Active/Active. If you do an Active/Passive cluster, unless you have another application to go on the second node, you basically have a server collecting dust. Since it's not doing anything else, the second instance is installed so that both servers can function as SQL Servers. Alternately, one could use the second node for any of the normal clustered applications.
K. Brian Kelley
http://www.truthsolutions.com/
Author: Start to Finish Guide to SQL Server Performance Monitoring
http://www.netimpress.com/shop/product.asp?ProductID=NI-SQL1
K. Brian Kelley
@kbriankelley
Viewing 6 posts - 1 through 5 (of 5 total)
You must be logged in to reply to this topic. Login to reply