SCSI RAID - PCI vs. Embedded Duplex

[csssa]

I've searched this forum and others and not found a definitive answer to this

Scenario:
I've got a DL380 G4 with a 6i Array controller. It does have the ability to do SCSI duplexing through the embedded array controller. I'd like to setup the first two drives in RAID 1 and the other four drives in RAID 5.

Question:
What is the difference and/or advantages of using a separate PCI-E SCSI Disk array controller for duplexing vs. the embedded duplexing.

Assumption:
Through the info I've found, it seems as though the only real reason to get the PCI card to do this is if the built in Array controller will not handle duplexing. I don't see any advantages.

Any info is greatly appreciated.

Thanks

[JAguilar]

The internal/embedded controllers usually don't have enough cache for heavy writes in the type of scenario you are describing. I would consider using the embedded for the RAID1 config and using an additional PCI Array controller that has the capability of expanding the cache and or port capabilities for future growth on the RAID5 config. This way you have top performance consistently.

Hope this helps,
Jose Aguilar-Systems Engineer
SunGard Availability Services,Inc.

[csssa]

Jose,

Thanks, that was better quality info than I've found anywhere. HP recommended this: Smart Array 6404/256 RAID Controller. It will handle 2 arrays but costs $1350.

Based on your suggestion, it seems like a single channel PCI array controller will do the trick. My new questions are:

- Will this scenario require more maintenance than one that will handle duplexing? Since we would be using 2 controllers it seems that there could be some conflict down the road.

- This server will be running Exchange 2003, given the sometimes heavy workload is it going to be smarter to get the more expensive card and allow it to handle both arrays?

Thanks again.

To anyone else with any good info, I thank you in advance