Re: Installing Linux on RAID

["Robert G. (Doc) Savage" <dsavage@peaknet.net>]

On Wed, 2004-09-29 at 00:06, Robert Citek wrote:
> On Tuesday, Sep 28, 2004, at 22:30 US/Central, Robert G. (Doc) Savage 
> wrote:
> > Like most hardware devices, you need the right software driver before
> > you can use it. I'm far more familiar with Red Hat than with SuSE, but
> > check your /var/lib/<kernel_version>/kernel/drivers/scsi directory for
> > the driver for your controller. If you can specify that driver during
> > installation, your RAID array should appear as a single /dev/sda 
> > device.
> 
> Out of curiosity, if linux doesn't know the driver, how can I know what 
> driver to specify for the controller?
> 
> For example, on our Dells use RAID cards and I would have no idea what 
> driver should be used for our RAID cards.  Yet, Linux "knows".  lspci 
> lists this:
> 
> $ sudo lspci -v -s 04:03
> 04:03.0 RAID bus controller: Dell Computer Corporation PowerEdge 
> Expandable RAID Controller 4/Di (rev 02)
>          Subsystem: Dell Computer Corporation: Unknown device 014a
>          Flags: bus master, stepping, 66Mhz, medium devsel, latency 32, 
> IRQ 18
>          Memory at f0000000 (32-bit, prefetchable) [size=128M]
>          Memory at fcd00000 (32-bit, non-prefetchable) [size=256K]
>          Expansion ROM at fcc00000 [disabled] [size=32K]
>          Capabilities: [c0] Power Management version 2
>          Capabilities: [d0] Message Signalled Interrupts: 64bit+ 
> Queue=0/1 Enable-
>          Capabilities: [e0] PCI-X non-bridge device.
> 
> And the driver reported by dmesg is megaraid:
> 
> megaraid: v1.18f (Release Date: Tue Dec 10 09:54:39 EST 2002)
> megaraid: found 0x1028:0x000f:idx 0:bus 4:slot 3:func 0
> scsi0 : Found a MegaRAID controller at 0xf8838000, IRQ: 18
> scsi0 : Enabling 64 bit support
> megaraid: [4.10:B111] detected 1 logical drives
> megaraid: supports extended CDBs.
> megaraid: channel[1] is raid.
> megaraid: channel[2] is raid.
> scsi0 : LSI Logic MegaRAID 4.10 254 commands 15 targs 5 chans 7 luns
> blk: queue c4838018, I/O limit 4095Mb (mask 0xffffffff)
> scsi0: scanning virtual channel 0 for logical drives.
>    Vendor: MegaRAID  Model: LD 0 RAID0   34G  Rev: 4.10
>    Type:   Direct-Access                      ANSI SCSI revision: 02
> 
> Fortunately, Linux somehow "knows" that megaraid is the right driver.  
> My question is how does it know?
> 
> Regards,
> - Robert
> OpenSource for Windows, Linux, and Mac OS/X
> http://www.cwelug.org/downloads
> 
> 
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Robert,

If I weren't a thousand miles from home I would probably be able to give
you a better answer. But I'm not, and bandwidth where I'm at is
pitifully low...

Dell calls their PowerEdge RAID Cards PERCs, and in your case it's a
PERC model 4/Di. FYI, one of its ancestors was the old American
Megatrends (AMI) MegaRAID. Dell supports Linux on its servers and PERCs
quite well. You might want to drop a note to Matt_Domsch@Dell.com. Matt
has been helping Dell customers on the Red Hat mail lists for several
years.

-- Doc
Robert G. (Doc) Savage, BSE(EE), CISSP, RHCE | Fairview Heights, IL
Fedora Core 1 kernel 2.4.22-1.2199.nptl on P-III/M IBM Thinkpad A22p
"Perfection is the enemy of good enough."
                         -- Admiral of the Fleet Sergei G. Gorshkov


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