zfs discuss - Dec 2009 - How to destroy ZFS pool with dump on ZVOL

Hi ZFS guys,

when playing with one of recent version of OpenSolaris GUI installer,
I have tried to restart it after previous failure.
However, the installer failed when trying to destroy previously created
ZFS root pool. It was discovered that this is due to the fact that dump
ZFS volume could not be released and thus subsequent ''zpool
destroy'' command
failed (as expected):

# zpool destroy -f rpool
cannot destroy ''rpool'': pool is busy

# zfs list rpool/dump
NAME         USED  AVAIL  REFER  MOUNTPOINT
rpool/dump   750M  9.93G   750M  -

# dumpadm
      Dump content: kernel pages
       Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
Savecore directory: /var/crash/opensolaris
  Savecore enabled: no
   Save compressed: on


There was a discussion which happened on zfs-discuss mailing list
some time ago about how dump ZVOL could be release and the recommended
approach was to try to move it to swap ZVOL - the attempt failed,
but dump ZVOL was released. That no longer seems to work:


# swap -l
swapfile             dev    swaplo   blocks     free
/dev/zvol/dsk/rpool/swap  8,1         8  2287608  2287608
# dumpadm -d swap
dumpadm: no swap devices could be configured as the dump device
# dumpadm
      Dump content: kernel pages
       Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
Savecore directory: /var/crash/opensolaris
  Savecore enabled: no
   Save compressed: on


Bug 13180 was filed against OpenSolaris installer to track this issue.

Could I please ask somebody from ZFS team to help install folks understand
what changed and how the installer has to be modified, so that it can
destroy ZFS root pool containing dump on ZVOL ?

Thank you very much,
Jan

Hi, Jan,

? 2009/12/9 20:41, Jan Damborsky ??:
> # dumpadm -d swap
> dumpadm: no swap devices could be configured as the dump device
> # dumpadm
>       Dump content: kernel pages
>        Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
> Savecore directory: /var/crash/opensolaris
>   Savecore enabled: no
>    Save compressed: on
>
>
> Bug 13180 was filed against OpenSolaris installer to track this issue.
>
> Could I please ask somebody from ZFS team to help install folks understand
> what changed and how the installer has to be modified, so that it can
> destroy ZFS root pool containing dump on ZVOL ?
I am doing the destroy ZVOL and zpool work a lot in my test cases.
What I required is the testing machine needs 2 hard disk, and add the 2nd
disk as swap under micro root:
# swap -a /dev/dsk/c2t1d0s0
then
# dumpadm -d swap
will pass, and I can do installation again and again.

But I am also hoping to get more neatly solution than requiring an 
additional storage.

Rgs
Jeffrey

Hi Jeffrey,


Jeffrey Huang wrote:
> Hi, Jan,
>
> ? 2009/12/9 20:41, Jan Damborsky ??:
>> # dumpadm -d swap
>> dumpadm: no swap devices could be configured as the dump device
>> # dumpadm
>>       Dump content: kernel pages
>>        Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
>> Savecore directory: /var/crash/opensolaris
>>   Savecore enabled: no
>>    Save compressed: on
>>
>>
>> Bug 13180 was filed against OpenSolaris installer to track this issue.
>>
>> Could I please ask somebody from ZFS team to help install folks 
>> understand
>> what changed and how the installer has to be modified, so that it can
>> destroy ZFS root pool containing dump on ZVOL ?
>
> I am doing the destroy ZVOL and zpool work a lot in my test cases.
> What I required is the testing machine needs 2 hard disk, and add the 2nd
> disk as swap under micro root:
> # swap -a /dev/dsk/c2t1d0s0
> then
> # dumpadm -d swap
> will pass, and I can do installation again and again.
Yep, I use similar approach - I create one spare slice on target disk
and then use it in the same way as you suggested.
>
> But I am also hoping to get more neatly solution than requiring an 
> additional storage.
Agreed - the solution for this problem is now being communicated
with ZFS team.

Thanks !
Jan