IBM Serveraid 6i configuration 1

[kleinicus]

Wondering how to go about a logical drive configuration. Need specifics.

Have IBM x235 with ServeRAID 6i
6 identical SCSI drives attached to ServeRAID 6i will be used in RAID 5 config for Exchange data storage.
2 identical SCSI drives attached to onboard RAID controller will be mirrored and will house Win2k3 OS.

Can't get IBM software to allow mirror of two drives and do RAID 5 on the other six. Please help.

 

[comtec17]

ftp://ftp.software.ibm.com/pc/pccbbs/pc_servers_pdf/59p6538.pdf

 

[catorze]

Just to satisfy my own curiosity, please explain why you are creating 2 separate logical drives for the data and OS. Of the 8 drives you have, you have the capacity of 6 drives, and fault tolerance, but no spare. If you configured 7 of the drives as a RAID-5 logical drive and the 8th as a hot spare, you would have better performance (one more head), fault tolerance, and a spare, with the same capacity.

 

[kleinicus]

I just became a consultant and I have a lot to learn. But, what they said makes sense to me...

The six drives in RAID 5 config are going to store the Exchange profiles. The two drives that are mirrored are going to contain just the operating system. They want to keep the Exchange data separate from the OS, which I completely understand. If something went wrong with the OS, they would still have the Exchange data intact, and vice versa. The OS is not quite as important as the Exchange data, so that's why it's mirrored while the Exchange data is on a separate logical drive with RAID 5. My understanding of this is still limited, but I'm learning more and more every day. Hope that makes sense.

 

[comtec17]

Best practice is to always keep the OS and Data Drives seperate.

 

[catorze]

Yes, from a partition-level, but the OS and the database have no clue about RAID. Building a single Array and Logical Drive impacts performance, but still allows you to keep the OS and data separate.

 

[kleinicus]

I may not be explaining this correctly, as, like I said, it's pretty new to me.

There are 6 identical drives in a row. They are all attached to a RAID card (ServeRAID 6i) in a PCI slot via a single cable. There are 2 more identical drives to the right of the first 6. They are both attached to the RAID interface built in to the mobo via a single cable. I'm pretty sure they said that they had to use logical drives to accomplish this separation, but I'm not sure about that. From what I understand, each set of physical hard drives is attached to a backplane, and the backplane is actually what connects via the single cable to each respective RAID interface.

Does this make any more sense? Please feel free to correct me if I'm mistaken about any of this.

 

[catorze]

Your explanation is fine, as is your configuration. I just wanted to confirm that your reasoning was based in something tangible - especially as a consultant. Too often, I have seen <new> MCSEs that swear the OS cannot be installed on a RAID5 configuration because the Microsoft training does not cover hardware RAID. They waste clients' money based on a book answer founded on software RAID, and do not fully understand the capabilities of the hardware they are "consulted" on <putting away the soapbox>.

 

[fluffybunny]

The IBM ServeRAID 6i adapter is a bit funny in that it is a specialised type of adapter. It has to be plugged in to a certain slot in the x235. You will know the slot as it is a bit longer than all the others. If you do not plug the adapter in to this slot, it will not work or may give you errors and chest pains .

Also, plugging in the ServeRAID 6i in to your system renders the built in SCSI to be disabled. You cannot use the built in SCSI for anything as it is disabled by the 6i.

Another thing, if you want to connect a tape drive to your system, better get a Ultra-320 SCSI adapter to connect it as the internal SCSI is being used by the 6i and your system will detect your tape drive but you will not be able to configure it.

Hope that helps...
Cheers.