Re: no utility / method to show association between HBA & non-sg BLOCK (scsi) devices - register_blkdev()

[Andrew Patterson <andrew.patterson@hp.com>]

On Wed, 2007-01-17 at 16:04 -0500, Douglas Gilbert wrote:
> Thayne Harmon wrote:
> >>>> On Thu, Jan 11, 2007 at  1:15 PM, in message <45A69AD6.60207@torque.net>,
> > Douglas Gilbert <dougg@torque.net> wrote: 
> >> Thayne Harmon wrote:
> >>> Gentlemen,
> >>>
> >>> hwinfo, lshal, sysfs do not show the relationship for non- sg BLOCK devices 
> >> with there 
> >>> associated Host Bus Adapter.
> >> All devices (i.e. logical units) have a 4 element tuple
> >> associated with them and the first element is the host
> >> number. A HBA contains one or more hosts. Then you can
> >> datamine in /sys/class/scsi_host/host<n> for whatever
> >> information you want.
> >>
> >>> Do you know of a utility or method that can show this?
> >> May I suggest lsscsi. That won't help you in the lk 2.4
> >> series and earlier though There are other methods by
> >> which the sg device corresponding to a "non- sg" block
> >> device (e.g. /dev/sdc) can be found.
> > 
> > [context - Linux testserver 2.6.16.21-0.8-smp i586]
> > 
> > There is no corresponding sg device. The device file is
> > /dev/cciss/c0d1.
> 
> Ok, I'm not familiar with the cciss driver. It looks like
> it lives outside the linux scsi subsystem but according
> to Documentation/cciss.txt it can subsequently "engage"
> the scsi subsystem??
> 
> If it is outside the scsi subsystem then it doesn't
> get corresponding sg devices. However as part of the
> block subsystem it might accept the SG_IO ioctl (if
> it accepts SCSI commands and it is implemented).
> 

Cciss is a block driver mostly outside of SCSI. It does interface into
the SCSI system for tape drives.

> > I tried lsscsi, however it would not print out the non-sg block devices.
> > 
> > I have attached the output of tree /sys and the output of lsscsi and uname.
> > One can search for cciss to find the devices and the driver.
> > I still cannot see a relationship.
> 
> <snip sysfs dump>
> 
> > [0:0:0:0]    storage COMPAQ   MSA1000          4.32  -       
> > [0:0:0:3]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sda
> > [0:0:0:4]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdb
> > [0:0:0:5]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdc
> > [0:0:0:6]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdd
> > [0:0:0:7]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sde
> > [1:0:0:0]    storage COMPAQ   MSA1000          4.32  -       
> > [1:0:0:3]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdf
> > [1:0:0:4]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdg
> > [1:0:0:5]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdh
> > [1:0:0:6]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdi
> > [1:0:0:7]    disk    COMPAQ   MSA1000 VOLUME   4.32  /dev/sdj
> 
> Well this looks like output from lsscsi. And those devices look
> like they could be associated with cciss, especially the
> compaq "storage" devices. These devices should have corresponding
> sg device nodes. Try "lsscsi -g".

These are Fibre-Channel Storage arrays, probably going through a QLogic
HBA.

> 
> Still a bit unclear as hosts 0 and 1 are Fibre Channel
> judging from the sysfs output for them.
> 
> Doug Gilbert
> 
> 
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-- 
Andrew Patterson
Hewlett-Packard Company