Best Performance RAID Config

[Paul Connolly]

I am ordering an ML370 server and wanted to spec three separate RAIDs.
RAID 1 for the OS (2-36Gb Drives)
RAID 5 for the database (3-36Gb Drives)
RAID 1 for the database log (2-36Gb Drives)

I have received various recommendations for the controller config. Some say purchase the 6402 and you can do 3 raids on 3 channels (Not the way I read the spec). Some have suggested 2-642 arrays (Although there are two channels, I thought only one was internal) An HP rep told me a 642 has two internal and 1 external. Then I was told the ML370 has on-board SCSI that can be config'd as RAID-1 thru software. How efficient is that?

My choice was the 6402 and a 642 smart array. I figured that's what I needed to do the three arrays thru hardware.

Server is a 2.8Ghz with 2Gb of RAM. 7 Drives with an Expansion Cage.

Any opinions would be greatly appreciated.

[Oleg Mochkin]

You need to use sa6402 with 2 internal connectors (not sa642 with only one internal connector). first connector is to 6-bays cage and second to 2-bay expansion cage. then you can configure desired RAID.

[Paul Connolly]

Understood, but don't I want a third unique channel for maximum throughput on each RAID. With just one 6402, don't I end up with a RAID-5 and a RAID-1 (in the 6 bay cage) on the same channel?

How much performance will I loose?

[thierry chabanne]

Hi,

I suppose you will be using the Compaq SCSI hot plug disks in your configuration so either their is something I don't know but a ML370 Server only has one internal drive cage with a capacity of 6 disks so I am not too sure how you will be having 7 disk in the server without using an external enclosure. (2 for Raid 1 and OS, 3 for raid 5 and data, and 2 for Raid 1 and logs). If I was you I would use a 6402 controller (2 chanels, one internal one external or 2 internal or 2 external)and connect the internal drive cage to one chanel then configure the first 2 disk in a raid1 configuration and the disk (with 2 volume on it one for the OS and the other one for the logs) and then the other disk I would configure them in a Raid 5 still using the same chanel since they would be in the same drive enclosure.
If you want to use 3 chanells then you should think about getting another controller as the 6402 has only 2 channels and 2 external enclosures or one with the option of connecting it to 2 scsi chanels.

Good luck and hope this has helped you a bit.

Thierry

[Paul Connolly]

Thanks for the feedback. Yes, I had spec'd the 2-bay cage in order to accommodate the extra drive.

What about performance sharing a channel?