CentOS virt - May 2017 - 4.9 kernel fails to boot because it didn't have the mpt3sas module

On Wed, May 17, 2017 at 10:07 AM, Sarah Newman <srn at prgmr.com> wrote:
> On 05/16/2017 09:04 PM, Jerry wrote:
> <snip>
> >
> > Turns out dracut was unable to mount the root file system.  So I went
> back
> > into the 3.10 kernel again to see if the mpt2sas or mpt3sas driver was
in
> > its initramfs file... and it wasn't:
> >
> >
> > $ sudo lsinitrd -k 4.9.25-27.el7.x86_64 | grep mpt
> > -rw-r--r--   1 root     root            0 May 16 12:39 etc/fstab.empty
> > -rw-r--r--   1 root     root           22 Nov  5  2016
> > usr/lib/kbd/unimaps/empty.uni
> >
> > For comparison:
> >
> > $ sudo lsinitrd -k 3.10.0-514.16.1.el7.x86_64 | grep mpt
> > -rw-r--r--   1 root     root            0 May 16 04:37 etc/fstab.empty
> > -rw-r--r--   1 root     root           22 Nov  5  2016
> > usr/lib/kbd/unimaps/empty.uni
> > drwxr-xr-x   2 root     root            0 May 16 04:37
> > usr/lib/modules/3.10.0-514.16.1.el7.x86_64/kernel/drivers/scsi/mpt3sas
> > -rw-r--r--   1 root     root       379021 Apr 12 08:51
> > usr/lib/modules/3.10.0-514.16.1.el7.x86_64/kernel/drivers/
> scsi/mpt3sas/mpt2sas.ko
> >
> >
> > So I added it:
> >
> >
> > $ sudo dracut --force --add-drivers mpt3sas
--kver=4.9.25-27.el7.x86_64
> > $ sudo lsinitrd -k 4.9.25-27.el7.x86_64 | grep mpt
> > Arguments: --force --add-drivers 'mpt3sas' --kver
'4.9.25-27.el7.x86_64'
> > -rw-r--r--   1 root     root            0 May 16 12:57 etc/fstab.empty
> > -rw-r--r--   1 root     root           22 Nov  5  2016
> > usr/lib/kbd/unimaps/empty.uni
> > drwxr-xr-x   2 root     root            0 May 16 12:57
> > usr/lib/modules/4.9.25-27.el7.x86_64/kernel/drivers/scsi/mpt3sas
> > -rwxr--r--   1 root     root       374152 May 16 12:57
> > usr/lib/modules/4.9.25-27.el7.x86_64/kernel/drivers/scsi/
> mpt3sas/mpt3sas.ko
> >
> >
> > After this I was able to get the 4.9 kernel to boot and Xen is now
> working.
>
> You should be able to make this change permanently from /etc/dracut.conf
> with
> the add_drivers+= line, or build a generic initrd with
hostonly="no" .
>
Thank you for this.  Adding mpt2sas or mpt3sas to the drivers+ line
worked.  Running dracut generates a proper image now.

> I don't know why it wasn't originally added.
>
> --Sarah
>
For some reason each of the 5, 6 & 7 releases have issues with the mpt2sas
driver (there isn't enough swiotlb allocated by default for the driver to
work properly, and the units for that parameter changed between 5 and 6).
It's like this driver has bad luck or something.

Jerry
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On 05/17/2017 01:30 PM, Jerry wrote:
> For some reason each of the 5, 6 & 7 releases have issues with the
mpt2sas
> driver (there isn't enough swiotlb allocated by default for the driver
to
> work properly, and the units for that parameter changed between 5 and 6).
> It's like this driver has bad luck or something.
To my best knowledge they shouldn't use swiotlb if you give the dom0 4GiB+
of RAM. I posted the exact same problem before and that was the recommendation
I got. It works.

--Sarah

On Wed, May 17, 2017 at 1:45 PM, Sarah Newman <srn at prgmr.com> wrote:
> On 05/17/2017 01:30 PM, Jerry wrote:
>
> > For some reason each of the 5, 6 & 7 releases have issues with the
> mpt2sas
> > driver (there isn't enough swiotlb allocated by default for the
driver to
> > work properly, and the units for that parameter changed between 5 and
6).
> > It's like this driver has bad luck or something.
>
> To my best knowledge they shouldn't use swiotlb if you give the dom0
4GiB+
> of RAM. I posted the exact same problem before and that was the
> recommendation
> I got. It works.
>
> --Sarah
>
I'm not keen on letting dom0 take up so much memory :)

I'm giving swiotlb 256MB of memory (swiotlb=131072 on el6/7) and that
resolved it for my configuration.

Jerry
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