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Note: There IS an authoritative answer on this e-mail. Be patient with me, please :)
On Wed, Sep 13, 2006 at 11:14:20PM -0500, Erick Perez wrote:
Does Centos/RHEL 4.4 supports the CERC 6-Channel SATA RAID Controller that comes with the Dell PowerEdge 830 Tower Server?
CERC meaning "Cost Effective Raid Controller", which doesn't bode well.
According to Dell[1]:
[QUOTE] CERC SATA 2S
The CERC SATA 2S RAID controller is a combination BIOS and driver-based software RAID solution, which uses the system motherboard's SATA controllers. It is not a hardware RAID solution such as the aacraid and megaraid controllers listed above.
Systems with this controller include the PowerEdge 800, SC1425, and 420SC.
Under Windows and Netware, there are special device drivers which operate in conjunction with the system BIOS to present the system SATA disks as a RAID volume.
Under Linux, the disks should be treated as two independent disks, which use the standard Linux "MD" software RAID layer for RAID 0 or 1 operation (if you so desire). System Documentation on support.dell.com[2] describe how to configure the system BIOS to either disable the RAID mode, or to set up the disks as two independent RAID volumes (effectively disabling the BIOS software RAID feature). [/QUOTE]
Notice: "It is not a hardware RAID solution". Also notice this might not be the controller you have.
On the other hand, some people claim otherwise[3]: "I did some digging this AM and everything points to it being a MegaRAID SATA 150-6 card (...)"
You might also take a look, subcribe or ask questions on the linux-poweredge mailing list[4]. That might be the best place to get help on this issue. This[5] particular post seems promising.
This last page[6] seems to indicate that it is really a magaraid-like controller, even providing a software to monitor it.
Of course all of that is very instructive, but doesn't give you an authoritative answer. Where should we look for that ? The kernel source, of course ("Use the source, Luke!").
The file drivers/scsi/aacraid/linit.c can be very instrutive on this particular case. On line 136 (or thereabout), you will find:
{ 0x9005, 0x0285, 0x1028, 0x0291, 0, 0, 38 }, /* CERC SATA RAID 2 PCI SATA 6ch (DellCorsair) */
And on line 211 (or thereabout):
{ aac_rx_init, "aacraid", "DELL ", "CERC SR2 ", 1 }, /* CERC SATA RAID 2 PCI SATA 6ch (DellCorsair) */
So we have a CERC SATA RAID with 6 channels from Dell, which really looks like the one you are talking about. It gets identified as CERC SR2, and is supported bu the aacraid driver. The only question left is, does this support exists out of the box on CentOS (4.4) ? Lets ask the module, of course. On /lib/modules/2.6.9-42.0.2.EL/kernel/drivers/scsi/aacraid, we can check it:
# strings aacraid.ko | grep CERC CERC SR2
There you go. Sorry for taking so much space to answer your question, but I'm hoping you can use my reasoning here for other things as well.
References: 1 - http://linux.dell.com/storage.shtml 2 - http://support.dell.com/support/edocs/systems/SC1425/en/index.htm 3 - http://www.linuxquestions.org/questions/showthread.php?t=336615 4 - http://lists.us.dell.com/pipermail/linux-poweredge/ 5 - http://marc.theaimsgroup.com/?l=linux-poweredge&m=112783948009432&w=... 6 - http://www.deadcat.net/search.php?action=browse%C2%A7ionid=16
- -- Rodrigo Barbosa "Quid quid Latine dictum sit, altum viditur" "Be excellent to each other ..." - Bill & Ted (Wyld Stallyns)