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Clustering and RAID controllers

I am in the process of trying to dig through the hardware selections for our production systems and have one or two questions that hopefully someone can help me with. I have a couple of dedicated servers from our Colo host and they are custom building our SQL cluster boxes what I want to know is when you install an Atto (this is an arbitrary selection, it could be an Adaptec or a Dell PERC) fibre raid controller card in one server and connect the array chassis of say 14 drives in a DAS configuration. Once you start the server and raid the drives, how does the second cluster server raid card see the drives? What I mean by this is that Machine 1’s raid controller setup the raid and has written data to the drives. How does the second card in an active/active setup know how the first raid card raided the drives? It seems to me that an incorrect setup could quickly corrupt the raid and break everything. Thanks in advance Scott for information. HTH Satya SKJ
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??? The DAS and SAN configurations I have worked on aren’t configured by an internal RAID controller on a host. They are configured internally and presented as LUN’s to a host or group of hosts, so I think you’re a little mistaken on how things work in this area. The server sees LUNs or drives, not RAID groups. When you use an internal RAID controller it’s a whole different ballgame. That’s one of the reasons you can’t cluster internal drive sets together across multiple servers. The internal RAID controllers are actually doing what a DAS or SAN configuration do for you. Make sense? Also, an active/active configuration is two disk arrays presented to two different servers. You end up with this: Server1 | Server2
Active-LUN1 Passive-LUN1
Passive-LUN2 Active-LUN2 Because of this, the second card doesn’t need to know anything about what’s going on with the first card. MeanOldDBA
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