Re: Booting from or using a Compaq RA4100 Array

[Rolf Eike Beer <eike-kernel@sf-tec.de>]

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Mark Schaefer wrote:
>Eike,
>
>I think I've resigned myself to the fact that it won't boot.  I've done a
>bit of digging by directly sending commands to the unit.  I'm not sure why
>I can't force scsi_scan to do a REPORT_LUN on it through the Black List,
>but what I know is that it reports luns as 0x40...00 - 0x40...MAX_LUNS -
>they are reported as flat addressing, according to the SCSI Architecture
>Manual.
>
>Since TYPE_RAID implements a standard (albeit deprecated), it might
>actually be worth trying to create a driver for it.  The real question I
>have is whether I could get at the drives simply by masking the LUN's like
>the cpqfc driver does, or whether something like BLIST_SPARSE_LUNS would
>do the trick, or maybe even a new blasklist entry like
>BLIST_FLAT_LUN_ADDRESSING.
>
>Here's a quote from cpqfcTSworker.c:
>// e.g., the Compaq RA4x00 f/w Rev 2.54 and above may report
>// LUNs 4001, 4004, etc., because other LUNs are masked from
>// this HBA (owned by someone else).  We'll make those appear as
>// LUN 0, 1... to Linux

I've looked around a bit in the LUN code some month ago as I was trying to get 
this to a state where it was sort of working. This code is as horrible as the 
rest of this driver, so I didn't really got the point what of this strange 
stuff is really needed and what was just caused by code monkeys on drugs.

I now got a card, but a 5121, so I can't test this stuff. And I don't have 
such an array :)

>I'm not sure what the direction of Linux is at this point, but there are a
>lot of RA4x00's out there for cheap and they (at least initially) seemed
>like a good entry-level FC RAID system.

Now the driver is buried and all the people with such hardware come out of 
their holes. Fascinating :)) I was thinking about a list related only to 
these things and/or writing a FAQ for this. What do the other people around 
think about this? MKP?

>Also, I'm not sure how strange of 
>a beast the RA4x00 is.  If it's a one-off, maybe I could create a specific
>driver for it that acts as a LUN masker.  If there are more, it may make
>sense to make the changes necessary to deal with flat addressing.
>
>At this point, I'm convinced that it would be a minor change to at least
>the scsi_scan code to deal with TYPE_RAID.  I'm a bit more concerned about
>how widespread a change like flat addressing would be.

I'm not really familiar with the low level SCSI code. James? Christoph?

Eike

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