zfs discuss - Jul 2011 - Changed to AHCI, can not access disk???

I have created some threads here about possible bugs in ZFS or bugs in ZFS beadm
(the PC reboots when I try too boot - why? bug in beadm??). But now it seems
that maybe there is no problems with ZFS. I will update my threads with
"SOLVED" tag when/if I find the solution.

Here is my problem:
I have an 1.5TB disk with OpenSolaris (b134, b151a) using non AHCI.
I then changed to AHCI in BIOS, which results in severe problems: I can not boot
the system.

I suspect the problem is because I changed to AHCI. Now I have changed back to
non AHCI, but still I can not boot the PC. Solaris gives an error message. How
can I solve this?

So this is what I have done:
1) 1.5TB disk worked fine with non AHCI
2) Switched to AHCI
3) Computer refuses to boot. There is an error message.
4) Switched back to non AHCI, booted from LiveCD and tried to import rpool. This
resulted in an immediate reboot.
5) Computer refuses now to boot when I try any OpenSolaris entry in GRUB. Shows
the same error message as in 3). However, WinXP boots fine though.




Now I have a new problem on the same theme.
A) Bought a Vertex 3, 240GB and turned on AHCI
B) Installed S11E, everything went fine. 
C) Later I tried to repair the problematic 1.5TB disk above, so I switched off
AHCI.
D) While using non AHCI, I booted off from liveCD S11E, and by mistake imported
the Vertex 3 rpool.
E) Now I can not boot from my Vertex 3, even if I switch on AHCI. It is the same
error message as in 3) and 5) above.



To summarize:
So the problems boils down to this:
Z) Solaris installs using AHCI
X) Switch to non AHCI
Y) Boot from LiveCD S11E and import the rpool
W) Turn back AHCI, and now Solaris refuses to boot. Why?

And vice versa: 
ZZ) Solaris installs non AHCI
XX) Switch to AHCI
YY) Boot from LiveCD S11E and import the rpool
WW) Turn off AHCI, and now Solaris refuses to boot. Why?
-- 
This message posted from opensolaris.org

> From: zfs-discuss-bounces at opensolaris.org [mailto:zfs-discuss-
> bounces at opensolaris.org] On Behalf Of Orvar Korvar
> 
> Here is my problem:
> I have an 1.5TB disk with OpenSolaris (b134, b151a) using non AHCI.
> I then changed to AHCI in BIOS, which results in severe problems: I can
not
> boot the system.
> 
> I suspect the problem is because I changed to AHCI. 
This is normal, no matter what OS you have.  It''s the hardware.

If you start using a disk in non-AHCI mode, you must always continue to use
it in non-AHCI mode.  If you switch, it will make the old data inaccessible.
Just change it back in BIOS and you''ll have your data back.  Then
backup
your data, change to AHCI mode (because it''s supposed to perform
better) and
restore your data.

On Tue, Jul 5, 2011 at 8:03 PM, Edward Ned Harvey
<opensolarisisdeadlongliveopensolaris at nedharvey.com>
wrote:
>> From: zfs-discuss-bounces at opensolaris.org [mailto:zfs-discuss-
>> bounces at opensolaris.org] On Behalf Of Orvar Korvar
>>
>> Here is my problem:
>> I have an 1.5TB disk with OpenSolaris (b134, b151a) using non AHCI.
>> I then changed to AHCI in BIOS, which results in severe problems: I can
> not
>> boot the system.
>>
>> I suspect the problem is because I changed to AHCI.
>
> This is normal, no matter what OS you have. ?It''s the hardware.
>
> If you start using a disk in non-AHCI mode, you must always continue to use
> it in non-AHCI mode. ?If you switch, it will make the old data
inaccessible.
Really? old data inaccessible?
These two links seem to say that the data is there, and it''s only a
matter whether the correct drivers are loaded or not:
http://en.wikipedia.org/wiki/Ahci
http://support.microsoft.com/kb/922976

So the question is, does similar workaround exists for (open)solaris?

-- 
Fajar

Ok, so I switch back and then I have my data back? 

But, it does not work. Because, meanwhile I switched, I tried to "zpool
import"
which messed up the drive. Then I switched back, but my data is still not 
accessible. 


Earlier, when I switched, I did not do a "zpool import" and when I
switched
back, I could access all my data. But now I have done a "zpool import"
while I
switched - which messes up things.

If I have done "zpool import" while switched, can I get back my rpool,
when I
switch back?






----- Original Message ----
From: Edward Ned Harvey <opensolarisisdeadlongliveopensolaris at
nedharvey.com>
To: Orvar Korvar <knatte_fnatte_tjatte at yahoo.com>; zfs-discuss at
opensolaris.org
Sent: Tue, July 5, 2011 3:03:50 PM
Subject: RE: [zfs-discuss] Changed to AHCI, can not access disk???
> From: zfs-discuss-bounces at opensolaris.org [mailto:zfs-discuss-
> bounces at opensolaris.org] On Behalf Of Orvar Korvar
> 
> Here is my problem:
> I have an 1.5TB disk with OpenSolaris (b134, b151a) using non AHCI.
> I then changed to AHCI in BIOS, which results in severe problems: I can
not
> boot the system.
> 
> I suspect the problem is because I changed to AHCI. 
This is normal, no matter what OS you have.  It''s the hardware.

If you start using a disk in non-AHCI mode, you must always continue to use
it in non-AHCI mode.  If you switch, it will make the old data inaccessible.
Just change it back in BIOS and you''ll have your data back.  Then
backup
your data, change to AHCI mode (because it''s supposed to perform
better) and
restore your data.

2011-07-05 17:11, Fajar A. Nugraha ?????:
> On Tue, Jul 5, 2011 at 8:03 PM, Edward Ned Harvey
> <opensolarisisdeadlongliveopensolaris at nedharvey.com>  wrote:
>>> From: zfs-discuss-bounces at opensolaris.org [mailto:zfs-discuss-
>>> bounces at opensolaris.org] On Behalf Of Orvar Korvar
>>>
>>> Here is my problem:
>>> I have an 1.5TB disk with OpenSolaris (b134, b151a) using non AHCI.
>>> I then changed to AHCI in BIOS, which results in severe problems: I
can
>> not
>>> boot the system.
>>>
>>> I suspect the problem is because I changed to AHCI.
>> This is normal, no matter what OS you have.  It''s the
hardware.
>>
>> If you start using a disk in non-AHCI mode, you must always continue to
use
>> it in non-AHCI mode.  If you switch, it will make the old data
inaccessible.
> Really? old data inaccessible?
Kind of. You can not access it now, right? ;)
> So the question is, does similar workaround exists for (open)solaris?
One of the ways is to have Solaris remap the boot devices.
When you change the boot device paths, and this includes
switching the access mode in BIOS (the controller number
and driver would probably change), Solaris would give you
a panic during boot and restart.

See this list or the internet for how to boot Solaris with KDB
(kernel debugger) and/or verbose mode - this should keep
the computer from rebooting and allow you to read the strings
on the screen, along the lines: zfs/vfs can''t mount the root,
panic, tried device paths /pci/something.

If that''s the case, you can return the BIOS to the mode where
Solaris boots okay, and try to fix up the EEPROM - rather its
x86 emulation in file /boot/solaris/bootenv.rc - which stores
"hardware configuration".

For an easy solution you can try to comment away the line
like (if it is there in the first place):
setprop bootpath /pci at 7b,0/pci1022,7458 at 11/pci1000,3060 at 2/sd at 3,0:a

Otherwise you may have to discover and insert the correct
line by using the livecd/installcd or the failsafe boot mode
(Solaris 10/SXCE) while and running "devfsadm -Cv"
in order for it to generate new disk/slice paths.
Then you can use "ls -la /dev/dsk" and see what PCI paths
are assigned (possibly this would lead you to /devices/
first, though).

There is another possible solution: boot from livecd while
in AHCI mode, and import/export the rpool. This may change
the device names/links in the ZFS pool header, helping
to "rename" them to the new controller numbers...


Good luck! ;)

On Tue, Jul 5, 2011 at 9:11 AM, Fajar A. Nugraha <work at fajar.net>
wrote:
> On Tue, Jul 5, 2011 at 8:03 PM, Edward Ned Harvey
> <opensolarisisdeadlongliveopensolaris at nedharvey.com> wrote:
>>> From: zfs-discuss-bounces at opensolaris.org [mailto:zfs-discuss-
>>> bounces at opensolaris.org] On Behalf Of Orvar Korvar
>>>
>>> Here is my problem:
>>> I have an 1.5TB disk with OpenSolaris (b134, b151a) using non AHCI.
>>> I then changed to AHCI in BIOS, which results in severe problems: I
can
>> not
>>> boot the system.
>>>
>>> I suspect the problem is because I changed to AHCI.
>>
>> This is normal, no matter what OS you have. ?It''s the
hardware.
>>
>> If you start using a disk in non-AHCI mode, you must always continue to
use
>> it in non-AHCI mode. ?If you switch, it will make the old data
inaccessible.
>
> Really? old data inaccessible?
    While I agree that you should not change the controller mode with
data behind it, I did do that on a Supermicro system running OpenSuSE
and Linux LVM mirrors with no issues. I suspect because Linux both
loads the AHCI drivers in the "mini-root" (to use a Sun term :-) and
that the LVM layer uses a private region on disk to identify the
device (much like both SLVM and ZFS).

-- 
{--------1---------2---------3---------4---------5---------6---------7---------}
Paul Kraus
-> Senior Systems Architect, Garnet River ( http://www.garnetriver.com/ )
-> Sound Coordinator, Schenectady Light Opera Company (
http://www.sloctheater.org/ )
-> Technical Advisor, RPI Players

2011-07-05 19:21, Paul Kraus wrote:
> While I agree that you should not change the controller mode with data 
> behind it, I did do that on a Supermicro system running OpenSuSE and 
> Linux LVM mirrors with no issues. I suspect because Linux both loads 
> the AHCI drivers in the "mini-root" (to use a Sun term :-) and
that
> the LVM layer uses a private region on disk to identify the device 
> (much like both SLVM and ZFS). 
Good point about the miniroot.

One more possible solution (component) would be this:

1) Set your root disk to AHCI or whatever you need
2) Boot from livecd
3) Import your rpool and mount the root filesystem into /a for example
4) Update device links:
# devfsadm -r /a -Cv
5) Update the miniroot
# bootadm update-archive -R /a
6) Export the rpool
7) Reboot and hope this helps ;)
//Jim

I have already formatted one disk, so I can not try this anymore. 



(But, importing the zpool with the name "rpool" and exporting the
rpool again, was successful. I can now use the disk as usual. But this did not
work on the other disk, so I formatted it)
-- 
This message posted from opensolaris.org

On 2011-Jul-05 21:03:50 +0800, Edward Ned Harvey
<opensolarisisdeadlongliveopensolaris at nedharvey.com>
wrote:
>> From: zfs-discuss-bounces at opensolaris.org [mailto:zfs-discuss-
>> bounces at opensolaris.org] On Behalf Of Orvar Korvar
...
>> I suspect the problem is because I changed to AHCI. 
>
>This is normal, no matter what OS you have.  It''s the hardware.
Switching to AHCI changes the device interface presented to the kernel
and you need a different device driver to access the data.  As long as
your OS supports AHCI (and that is true of any OS that supports ZFS)
then you will still be able to access the disks - though the actual
path to the disk or disk device name will change.
>If you start using a disk in non-AHCI mode, you must always continue to use
>it in non-AHCI mode.  If you switch, it will make the old data inaccessible.
Only if your OS is broken.  The data is equally accessible in either
mode.  ZFS makes it easier to switch modes because it doesn''t care
about the actual device name - at worst, you will need an export and
import.

-- 
Peter Jeremy
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On Tue, Jul 05, 2011 at 09:03:50AM -0400, Edward Ned Harvey
wrote:
> > I suspect the problem is because I changed to AHCI. 
> 
> This is normal, no matter what OS you have.  It''s the hardware.
That is simply false.
> If you start using a disk in non-AHCI mode, you must always continue to use
> it in non-AHCI mode.  If you switch, it will make the old data
inaccessible.
Utterly not true.

Even in this case, the problem is not access to the data. The problem
is with booting from the device / mounting as root, because solaris
(and windows) embed device name/path information into configuration
data critical for booting. 

Even these OS''s will be able to access data disks via either
controller mode/type if the boot time issue is removed.

Other operating systems that don''t depend on embedded device path
information in the boot sequence can switch easily between IDE/AHCI
modes for boot disks, or indeed between other controller types
(different scsi controllers, booting native vs as a VM, moving disks
between boxes, etc).

The fact that Solaris fails to tolerate this is a bug.  In addition
to other problems, this bug manifests when trying to use removable usb
sticks as boot media/rpool, because usb device names are constructed
based on port and topology in some cases.  I have also been bitten by
it in the past when rearranging controllers into different slots.
> Just change it back in BIOS and you''ll have your data back.  Then
backup
> your data, change to AHCI mode (because it''s supposed to perform
better) and
> restore your data.
In this case, the recorded device path has probably been mangled, and
will need to be repaired before the pool is bootable again.  The pool
should, however, be accessible as data from an independent boot.

--
Dan.
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