September 23, 2010 at 6:14 am
I have a requirement for a SQL Server 2008 cluster that has two active nodes. One active node will be used as a 'writing' db, and then will be replicated to the other 'active' node which will be used for 'reading'. The reason for this is that both operations by themselves are resource intensive, so apparently end-users will get better performance from the separation.
I dont see the need to have four servers for this configuration though. Is it possible to have this as a three node cluster, where if either server fails, it fails over to the single passive server?
September 23, 2010 at 6:24 am
yes it is, as long as the passive node is capable of supporting both instances at the same time (or the SLA states that a performance degradation is acceptable in this set up)
MS would refer to this as an n+1 cluster
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September 23, 2010 at 6:26 am
So do I set this up as two clusters? Or are there better instructions somewhere?
September 23, 2010 at 6:30 am
its one 3 node cluster with two instances sitting on it.
set up is the same you will have two SQL resource groups
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September 23, 2010 at 6:36 am
as you configuring, so it will be active-active-passive server and you need three well prepared server.
While shortilisting the hardware limitation, please keep in mind that at emergency your one server will be taking load of 2 server.
So if you both active fail then your passive will be taking load of both active.
There are document on MS site, which gives the min set of limitation for cluster configuration.
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Ashish
September 23, 2010 at 6:51 am
So do I need to quorums? How do I get two servers to read from the same quorum?
September 23, 2010 at 8:14 am
Firstly, a cluster is either active\passive or active\active, thats it
madler-797963 (9/23/2010)
So do I need to quorums? How do I get two servers to read from the same quorum?
The servers do not particularly read from the quorum, the cluster service does everything needed with the quorum device. The quorum takes different forms depending upon the clustering technology used. Are you using a Windows 2003 cluster or a Windows 2008 cluster?
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September 23, 2010 at 9:00 am
This one is going to be 2008. I've never set up before on 2008, but I've done about 4 2003 Active/Passive clusters.
September 23, 2010 at 11:37 am
The quorum options have changed with Windows 2008, check out technet for full details
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"Ya can't make an omelette without breaking just a few eggs" 😉
September 23, 2010 at 11:59 am
Excellent. Thanks everyone for all your help!
October 5, 2010 at 1:20 pm
Don't forget that you'll also need to make sure both SQL Server instances have different instance names (ie: MSSQLSERVER (default) and MSSQLSERVER2.)
You'll also only need one quorum, if you decide to use one for failover detection purposes.
October 5, 2010 at 2:12 pm
Scott Paulson (10/5/2010)
You'll also only need one quorum, if you decide to use one for failover detection purposes.
The quorum is present whatever. Whether majority, majority and file share or majority and disk, it's part of the initial Windows cluster deployment.
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"Ya can't make an omelette without breaking just a few eggs" 😉
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