DL320 G4 SATA Raid & Hot Plug

[Hynes, C.]

Hello all,

I would like to implement Raid1 and hot plug functionality on a DL320G4.
Am I correct in assuming that real hardware based Raid cannot be achieved with the embedded SATA controller (I read it's a fakeraid chip in some other thread)?
Would I need to add the HP 8 internal port 64/133 PCI-X SAS HBA, or the HP 6 port SATA RAID controller?
I am planning on installing Linux FC4 on the server. Would the Raid1 configuration be totally transparent to the OS (i.e., would I see only one device relative to the mirrored disks?)

Thank you,
Claudio

[Robert S. Carr]

Claudio:

If you're thinking of a RAID 1, you need 2 disks so a 6 or 8 port controller is a bit of a waste if that's your only plan.

If you are considering RAID 0+1, this is where a 2+ port controller makes more sense. Perhaps when the comment 'fake RAID' was made it was made in the context the chip may only support RAID 0 or RAID 1 with 2 hard drives. These are the two simplests RAIDs and you can even find software to do the job for you.

It's RAID 0+1, RAID 3, and RAID 5 where a hardware controller really becomes worth the money.

The big question is, can you configure the RAID from Linux FC4? I'm pretty sure you can but you've got to make sure the software is available for you to config the RAID.

Good luck.

Rob

[Hynes, C.]

Hi Robert,

Thank you for your reply. At present I am planning only for drive mirroring and would like to have hot swappable drives. I agree that an 8 port card seems like a waste but, quoting the quickspecs:
"Please note that Serial ATA hot-plug capability and drive LEDs are not supported by the DL320 G4 embedded SATA storage controller. The purchase of the HP 8 Internal Port SAS HBA with RAID and the DL320 Hot Plug SAS/SATA Cable Option Kit is required for Hot Plug and LED SAS/SATA support"
(On a side note: it's very confusing that such information be more or less concealed inside the quickspecs when the specifications pages have "hot plug sata" written all over the place)
Regarding RAID configuration, does true hardware RAID need specific drivers for the OS being installed?
I was supposing that a hardware solution would mask the actual drive arrangement by showing only 1 device (considering one mirrored pair) to the OS and that RAID setup would occur by accessing the controller's software right after power on as in the case of BIOS setup.
I would then need some utility to monitor the RAID's status from withing the OS during normal operation, but that might be less of a problem.
I'd really prefer not implementing software RAID on the server.

Thanks for your support,
Claudio

[Chris Saindon]

Hello,

You are absolutely correct about needing the 6 or 8 port card to use the hot-plug functionality. The embedded chip does not support it.

The on board RAID is actually called ROC, or Raid on Chip. It is a hardware RAID, but it works like Windows software RAID does. It is actually controlled through the server BIOS.

Here is a link to find any HP branded drivers running whatever O/S you need. If it is not available, unfortunately HP does not have a driver for that specific O/S.

http://h18023.www1.hp.com/support/files/server/us/index.html

As for the transparency to the O/S. Both RAID methods (ROC and PCI Card) will be completely transparent to the O/S. ROC is only editable through the BIOS, the PCI cards do have a SATA Raid Manager. This link is for Windows 2003, but again, depending on your O/S, it may or may not be available.
http://h18023.www1.hp.com/support/files/server/us/download/23531.html

Hope this helps clarify things

Chris