zfs discuss - Aug 2009 - shrink the rpool zpool or increase rpool zpool via add disk.

Hi all:
First; it is possible modify the boot zpool rpool after OS installation...?
I install the OS on the whole 72GB harddisk.. it is mirrored so If I want to
decrease the rpool; for example resize to a 36GB slice it can be done?
As far I remember on UFS/SVM I was able to resize boot OS disk via detach
mirror (so tranforming to one-way mirror); ajust the partitions then attach
de mirror. After sync boot form the resized mirror; re-doing the resize on
the remaining mirror and attach mirror and reboot.
Dowtime reduced to a reboot times.

Second: In the first can''t be done; I was guessing I could increase
rpool
size via adding more hard disk. As you know that must be done with SMI
labeled hard disk; well I have tried change  the start cyl; changed the
label type almost everything and I still get the error
 zpool add rpool mirror c1t2d0 c1t5d0
cannot label ''c1t2d0'': EFI labeled devices are not supported
on root pools.

partition> print
Current partition table (original):
Total disk cylinders available: 24620 + 2 (reserved cylinders)

Part      Tag    Flag     Cylinders         Size            Blocks
  0       home    wm       0 - 24619       33.92GB    (24620/0/0) 71127180
  1 unassigned    wm       0                0         (0/0/0)            0
  2     backup    wm       0 - 24619       33.92GB    (24620/0/0) 71127180
  3 unassigned    wm       0                0         (0/0/0)            0
  4 unassigned    wm       0                0         (0/0/0)            0
  5 unassigned    wm       0                0         (0/0/0)            0
  6 unassigned    wm       0                0         (0/0/0)            0
  7 unassigned    wm       0                0         (0/0/0)            0
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Randall Badilla wrote:
> Hi all:
> First; it is possible modify the boot zpool rpool after OS 
> installation...? I install the OS on the whole 72GB harddisk.. it is 
> mirrored so If I want to decrease the rpool; for example resize to a 
> 36GB slice it can be done?
> As far I remember on UFS/SVM I was able to resize boot OS disk via 
> detach mirror (so tranforming to one-way mirror); ajust the partitions 
> then attach de mirror. After sync boot form the resized mirror; 
> re-doing the resize on the remaining mirror and attach mirror and reboot.
> Dowtime reduced to a reboot times.
>
Yes, you can follow same procedure with zfs (details will differ of course).
> Second: In the first can''t be done; I was guessing I could
increase
> rpool size via adding more hard disk. As you know that must be done 
> with SMI labeled hard disk; well I have tried change  the start cyl; 
> changed the label type almost everything and I still get the error
>  zpool add rpool mirror c1t2d0 c1t5d0
> cannot label ''c1t2d0'': EFI labeled devices are not
supported on root
> pools.
once you manually sliced the disks on SMI label then when creating a 
mirror you need to specify which slice zfs should use. If you specify a 
disk without providing a slice zfs always try to put new EFI label in 
place and use entire disk but since in above example you are trying to 
add to rpool and only SMI is allowed it fails.

(zpool add rpool mirror c1t2d0s0 c1t5d0s0)

However I''m not sure if raid-10 (two mirrors striped in your case) is 
allowed for rpools...

-- 
Robert Milkowski
http://milek.blogspot.com

>Randall Badilla wrote:
>> Hi all:
>> First; it is possible modify the boot zpool rpool after OS 
>> installation...? I install the OS on the whole 72GB harddisk.. it is 
>> mirrored so If I want to decrease the rpool; for example resize to a 
>> 36GB slice it can be done?
>> As far I remember on UFS/SVM I was able to resize boot OS disk via 
>> detach mirror (so tranforming to one-way mirror); ajust the partitions 
>> then attach de mirror. After sync boot form the resized mirror; 
>> re-doing the resize on the remaining mirror and attach mirror and
reboot.
>> Dowtime reduced to a reboot times.
>>
>Yes, you can follow same procedure with zfs (details will differ of course).
You can actually change the partitions while you''re using the slice.
But after changing the size of both slices you may need to reboot

I''ve used it also when going from ufs to zfs for boot.
>However I''m not sure if raid-10 (two mirrors striped in your case)
is
>allowed for rpools...

Nope: a mirror will work (just boot from one of the devices until the
kernel is loaded) and you can even compress the root filesystem (with the
standard compress algorithm)

Casper

Casper.Dik at sun.com wrote:
>> Randall Badilla wrote:
>>     
>>> Hi all:
>>> First; it is possible modify the boot zpool rpool after OS 
>>> installation...? I install the OS on the whole 72GB harddisk.. it
is
>>> mirrored so If I want to decrease the rpool; for example resize to
a
>>> 36GB slice it can be done?
>>> As far I remember on UFS/SVM I was able to resize boot OS disk via 
>>> detach mirror (so tranforming to one-way mirror); ajust the
partitions
>>> then attach de mirror. After sync boot form the resized mirror; 
>>> re-doing the resize on the remaining mirror and attach mirror and
reboot.
>>> Dowtime reduced to a reboot times.
>>>
>>>       
>> Yes, you can follow same procedure with zfs (details will differ of
course).
>>     
>
> You can actually change the partitions while you''re using the
slice.
> But after changing the size of both slices you may need to reboot
>
> I''ve used it also when going from ufs to zfs for boot.
>
>   
But the OP wants to decrease a slice size which if it would work at all 
could lead to loss of data.


-- 
Robert Milkowski
http://milek.blogspot.com

On 08/29/09 05:41, Robert Milkowski wrote:
> Casper.Dik at sun.com wrote:
>>> Randall Badilla wrote:
>>>    
>>>> Hi all:
>>>> First; it is possible modify the boot zpool rpool after OS 
>>>> installation...? I install the OS on the whole 72GB harddisk..
it
>>>> is mirrored so If I want to decrease the rpool; for example
resize
>>>> to a 36GB slice it can be done?
>>>> As far I remember on UFS/SVM I was able to resize boot OS disk
via
>>>> detach mirror (so tranforming to one-way mirror); ajust the 
>>>> partitions then attach de mirror. After sync boot form the
resized
>>>> mirror; re-doing the resize on the remaining mirror and attach 
>>>> mirror and reboot.
>>>> Dowtime reduced to a reboot times.
>>>>
>>>>       
>>> Yes, you can follow same procedure with zfs (details will differ of
>>> course).
>>>     
>>
>> You can actually change the partitions while you''re using the
slice.
>> But after changing the size of both slices you may need to reboot
>>
>> I''ve used it also when going from ufs to zfs for boot.
>>
>>   
>
> But the OP wants to decrease a slice size which if it would work at 
> all could lead to loss of data.
You can''t decrease the size of a root pool this way (or any way, right 
now).  This is just a specific case of bug 4852783 (reduce pool 
capacity).  A fix for this is underway, but is not yet available.

Lori
>
>