Re: Pb with external RAID controller in lk 2.4

Fabien Salvi
2002-05-23T09:01:04Z

Patrick Mansfield wrote:
>
> On Wed, May 22, 2002 at 09:49:01AM +0200, Fabien Salvi wrote:
> > Fabien Salvi wrote:
>
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sda at scsi0, channel
> > > 0, id 0, lun 0
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sdb at scsi0, channel
> > > 0, id 0, lun 1
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sdc at scsi0, channel
> > > 0, id 0, lun 2
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sdd at scsi0, channel
> > > 0, id 0, lun 3
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sde at scsi0, channel
> > > 0, id 0, lun 4
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sdf at scsi0, channel
> > > 0, id 0, lun 5
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sdg at scsi0, channel
> > > 0, id 0, lun 6
> > > May 17 16:19:36 node01 kernel: Attached scsi disk sdh at scsi0, channel
> > > 0, id 0, lun 7
> > > May 17 16:19:36 node01 kernel: Attached scsi CD-ROM sr0 at scsi2,
> > > channel 0, id 5, lun 0
> > > May 17 16:19:36 node01 kernel: sym2:5: FAST-20 SCSI 20.0 MB/s ST (50.0
> > > ns, offset 16)
> > > May 17 16:19:36 node01 kernel: sr0: scsi3-mmc drive: 17x/40x cd/rw
> > > xa/form2 cdda tray
> > > May 17 16:19:36 node01 kernel: Uniform CD-ROM driver Revision: 3.12
> > > May 17 16:19:36 node01 kernel: sym0:0: FAST-20 SCSI 20.0 MB/s ST (50.0
> > > ns, offset 16)
> > > May 17 16:19:36 node01 kernel: SCSI device sda: 17776640 512-byte hdwr
> > > sectors (9102 MB)
> > > May 17 16:19:36 node01 kernel: Partition check:
> > > May 17 16:19:36 node01 kernel: sda: sda1 sda2 sda3 sda4
> > > May 17 16:19:36 node01 kernel: SCSI device sdb: 17776640 512-byte hdwr
> > > sectors (9102 MB)
> > > May 17 16:19:36 node01 kernel: sdb: sdb1
> > >
> > > Like you can see, it founds 8 disks !
> > > I tried to increase max_scsi_luns to 64 to see if it will find as many
> > > disks as luns, but it does not go after lun7 ==> 8 disks
> > >
>
> > Gérard and Doug, thanks for your help.
> >
> > But, in fact, after re-reading my email, I've seen it's confusing
> > because I didn't explain correctly the problem.
> >
> > The lk 2.2 has the good comportment : it only finds the 2 disks.
> > And, that's ok, I have really only 2 disks to be seen.
> >
> > The problem is with the 2.4 kernel that finds 8 disks but it should only
> > see 2 disks, because there is only 2 disks !
> >
> > The other disks are not accessible :
> > $fdisk /dev/sdc
> >
> > Unable to open /dev/sdc
> >
> > It's the same from sdc to sdh...
> >
> >
> > I've tried in the 2.4 kernel to increase the max_scsi_luns because I
> > thought lk may find as disks as many luns I have, but it's not the case
> > : it don't find more than 8 disks (maybe this is reassuring...).
> >
> > So here is the problem : the lk 2.4 finds more disks than I have !
>
> The 2.4 kernel won't scan past LUN 7 for SCSI-2 devices - you can try
> modifying the code and set the max to 31 in scsi_scan.c.
>
> The device is probably setting the peripheral-qualifier (PQ) such that the
> scan continues but the device is marked offline, this is just annoying
> if do not have a lot of them. In scsi_scan.c:
>
> /* Use the peripheral qualifier field to determine online/offline */
> if (((scsi_result[0] >> 5) & 7) == 1) SDpnt->online = FALSE;
> else SDpnt->online = TRUE;
>
> The above means that sd will attach to the device, but won't try to read
> capacity etc, and an open of the device will fail. Redhat kernels have
> some changes to avoid this problem, there was also a PQ patch posted
> some time ago (it would make sense to put it into 2.5, especially now that
> the inquiry data is retained, and avoid setting online to FALSE).
>
> There is also some odd case (AFAIR when initializing sd after the adapter has
> been loaded and scanned the devices) where the online gets reset to TRUE
> and causes sd.c to fail trying to read the non-existent LUN.

Thanks for your help Patrick, I think it's the solution.
Well, like I have not so many disks found, I will let them in this
state...

-------------
Fabien SALVI Centre de Ressources Informatiques
Archamps, France -- http://www.cri74.org
PingOO GNU/linux distribution : http://www.pingoo.org