zpool autoexpand property [PSARC/2008/353 Self Review]

[Matthew Ahrens]

Torrey McMahon wrote:
> Matthew Ahrens wrote:
>> [SNIP]
>>
>> D. MANPAGE DIFFS
>>
>> The following text will be added under the "Properties" section:
>>
>>    autoexpand=on | off
>>
>>        Controls automatic pool expansion when the underlying LUN is
>>        grown. If set to "on", the pool will be resized according to the
>>        size of the expanded device. If the device is part of a mirror or
>>        raidz then all devices within that mirror/raidz group must be
>>        expanded before the new space is made available to the pool. The
>>        default behavior is "off". This property can also be referred to
>>        by its shortened column name, "expand". 
> 
> 
> Any particular reason the default is off?

1. to preserve the existing behavior

2. if they expanded the LUN and for some reason didn't want ZFS to use it 
(eg, they wanted to put a new slice on it for something else), we don't want 
to unexpectedly and irrevocably grab this space.

--matt