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SQL 2005 on Active/Active Cluster

I am about to embark on an attempt at setting up my first clustered server, which will be running SQL 2005 and W2003 Ent. Server on 2 nodes. I will have 3 instances of SQL running. I would like to have one instance running on the first node and 2 other instances running on the second. I assume this would require an active/active configuration. I also have 7 72.8 Gig hard drives in a HP MSA500 cluster disk array. I have several questions? 1. Would the SQL instances run quicker this way?
2. Can I safely assume that, if one failed, the other would take up the responsibility for all SQL instances?
3. What would be the best RAID configuration?
4. Would it be best if I put one drive physically in each server and left only 5 for the RAID array? Thank you for your help.
1. They wouldn’t run any quicker than if they were on a standalone machine. Though instance on seperate machines (or seperate nodes) do not compete for CPU etc so may perform better.
2. Yes
3 & 4. When clustering you must dedicate disks to each instance of SQL. You cannot share disks between instances. Which means for 3 instances you will need quite a few disks. The RAID config depends on your requirements. There is no difference planning RAID for clusters as there is to non clustered instances. Also note that SQL on a cluster cannot store any data or log files on internal drives – only shared DAS/SAN drives. you may find this useful:http://msdn2.microsoft.com/en-us/library/ms179530.aspx Simon

Thank you for your response. It is very helpful. However, I do have a follow-up question or two, if you don’t mind?
How many disks do you recommend for 3 instances?If I were to use RAID 1+0, would 6 disks suffice in the disk array?
Secondly, do I need a local disk in each server or can I use only the disks in the external array? Thanks Again
Hello there. i managed to set up a virtual server cluster with win2k3 server and to install one virtual sql2005 server but i dont manage to set up a second virtual sql2005 server in the cluster. does anyone know about a step-by-step guide in the web indicating how to set up an active/active sql2005 on a win2k3 server cluster?
thanks mike