DL380 G4 - How to properly configure raid arrays

Question

All,

I have a DL380 G4 server with the following drives:

• 2x 36.4GB - 15K
• 2x 36.4GB - 10K
• 2x 300GB - 10K

I'm trying to figure out how best to configure these drives. This is the first time I'm working with an HP servers. It has an HP Smart Array 6i controller and a total of 6 drive bays. I don't need to use all of them.

The target OS most likely will be CentOS 5.5.

Any insight would be appreciated.

Thanks.

EDIT:

• This will be a CPanel webserver (with MySQL, Exim, Apache, etc.) I'm getting off of a dedicated server to get the machine colocated.
• When I fired up the SA 6i configuration utility, it didn't give me a RAID 1 option. Just 5, 1+0, and 0. I'll see if the firmware needs to be updated tomorrow morning.

Answer 1

If I remember correctly on that RAID controller the 1+0 option will let you create a two disk mirror. I can't remember the logic behind it but I remember it seeming dumb.

Since it's a new system there is no harm in trying.

Mezgani's recommendations are pretty much spot on too :-)

Answer 2

With three mismatched pairs of drives, your best bet is three RAID 1s.

Answer 3

We need more information about the usage of this machine, in the fact for a standard installation :
I let it RAID 1 at all and i set up disks like that :

• 2x 36.4GB - 15K => OS partition
  
• 2x 36.4GB - 10K => Log partition
  
• 2x 300GB - 10K => Data partition
  

Answer 4

the raid option 1+0 is the right. I would use the raid 1 with the 15k disks for logs or the mysql database, as usually databases or logs have the most disk i/o

Answer 5

I don't have a G4 handy, so I can't be positive. At a previous gig earlier in the year I did set up system partitions to be RAID1. I don't remember it being 1/0, but if you only have two drives selected in the config utility it will be the same.

Are you sure that the controller firmware is up to date? The current version for the 6i controller is v2.84 (A), dated 15 July, 2008.

You can get drivers, etc here, and the firmware here. Just make sure that you are looking at the 6i controller, and not the 641/642 or 6400 controllers.

Answer 6

Let the G4's controller do the work of mirroring and create 3x RAID1 from each pair of disks. Then use the three logical devices in your Linux LVM and create filesystems as you like.

That said, with 300 GB at hand, I consider the 36 GB disks a waste of power, unless you're really pressed for space and/or have a need to do intensive I/O on dedicated disks.

Answer 7

I would use two of the 10k 36rpm drives as a mirror for boot/system, and the 300s for Raid-5. I would also purchase two more 300gig drives, swap one for one of hte unused 36gb 15krpm drives and keep a 36 and a 300 online as hot-spares and then the two extra drives (another 36 and another 300) as cold spares.

Answer 8

36GB for a log partition seems excessive to me.

Unless you have some big need for hardware raid, Just use the software raid built into Linux. I would do all 36GB drives into a raid 5, then LVM them into your different partitions you need for the OS. "/var /home /swap" if you want to go that route. Use the two 300GB partitions into a Raid 1 for your data.

One of the big things I don't like in hardware raids is that it limits your access to the real drives. With a software raid, I can use smart to monitor each drive and replace them before they fail.