Re: Installing > 1 instance on a cluster node? - 01-14-2004 , 03:04 PM

Unless it snows.

"Mike Epprecht [SQL Server MVP]" <mike (AT) NOSPAMepprecht (DOT) net> wrote

Quote:

They all install simultaneously so there will be no perceived difference. -- -------------------------------- Mike Epprecht, Microsoft SQL Server MVP Epprecht Consulting (PTY) LTD Johannesburg, South Africa Mobile: +27-82-552-0268 IM: mike (AT) NOSPAMepprecht (DOT) net Specialist SQL Server Solutions and Consulting "Benny Koh" <anonymous (AT) discussions (DOT) microsoft.com> wrote in message news:04be01c3da4c$5d1ac130$a601280a (AT) phx (DOT) gbl... One more question: If I want to install SQL patches (eg Service Pack 3a), on an instance, will the SQL downtime for this instance be longer in a 2-node cluster versus a 4-node cluster? Benny -----Original Message----- Comments Inline "Mike Epprecht [SQL Server MVP]" mike (AT) NOSPAMepprecht (DOT) net> wrote in message news:%23JH%23w9b2DHA.2528 (AT) TK2MSFTNGP09 (DOT) phx.gbl... Hi Geoff has the luxury of having a spare box, just waiting to take over one of the nodes. In his scenario, if you loose 2 nodes, it does get interesting, but then you have other things to worry about. In effect, it is Active/Active/Active/Passive. As Mike notes, I have a 'spare' system that can take over. That way, I can set up my SQL instances to use all the resources on each node and still have failover room. As he also notes, things get interesting when more than node goes down. However, it isn't that hard. I simply reduce the memory footprint of each instance and in theory, I can run them all on one box. I haven't tried that, but I have run with two nodes offline during off-peak hours. With 4 boxes, 2x2 nodes is easier to maintain as you have to worry less about making sure that 4 instances are exactly the same over the cluster. Yep. Matching the nodes isn't simple, but good documentation and practices will help. If you don't have those you won't have a highly available system anyway. When you apply a SQL Service Pack, it takes the whole cluster offline. In a 2x2, you have only 1 cluster down at a time, whilst in a 1x4, everything is offline and might not come up again (Murphy's law is applicable to clusters too) Applying a service pack only takes the particular instance offline. No different than with a 2-node cluster. And yes, Murphy is the patron saint of computer science. Rolling reboots can take a while (especially on these Unisys boxes), but you aren't any more vulnerable than on a 2-node cluster. Depending on how much resilience you can afford, 2x2, 1x4 or 3x4 are all good options. 3x4 works for me because I really needed 3 instances and SQL will only install on 4 nodes per instance, so this is all we can do for now. Perfect match. YMMV. -- Geoff N. Hiten Microsoft SQL Server MVP Senior Database Administrator Careerbuilder.com Cheers -------------------------------- Mike Epprecht, Microsoft SQL Server MVP Epprecht Consulting (PTY) LTD Johannesburg, South Africa Mobile: +27-82-552-0268 IM: mike (AT) NOSPAMepprecht (DOT) net Specialist SQL Server Solutions and Consulting "Benny Koh" <anonymous (AT) discussions (DOT) microsoft.com> wrote in message news:082901c3d9af$930e54c0$a401280a (AT) phx (DOT) gbl... Hi Geoff, can you please explain why you found N-1 to be the best for you? Need to evaluate this configuration was well as the 2 2-node clusters that Mike recommended. -----Original Message----- You actually install each instance on all nodes, unles you restrict certain instances to certain node. I have a four node cluster with three instances, configured as you describe. That way, each instance can use the full resources of each node while still having full capacity in the event of a failover. With a cluster, you will have to leave some resources available if a node goes offline. Whether you leave some memory and processor capability on all nodes or on just one node is your choice. Personally, I have found the N-1 scenario the best. -- Geoff N. Hiten Microsoft SQL Server MVP Senior Database Administrator Careerbuilder.com "Benny Koh" <anonymous (AT) discussions (DOT) microsoft.com wrote in message news:02e201c3d8d2$a8181c30$a501280a (AT) phx (DOT) gbl... Hi, I have a set of 4 servers coming in to be installed as a cluster running Win 2003 Enterprise with SQL2000, all to be connected through Fibre Channel to a SAN. I am trying to figure out how many instances to install in this cluster. I want to utilise all nodes, so there will be at least 4 instances. What are the pros and cons of installing more than 1 instance on a node? TIA!! . .