So if I use a feature which has a new compression scheme (just to pick an
example) and then I later move the pool to an OS which doesn't support that
scheme, how could this not disable access to the data?

It's that kind of concern that has kept me on 28. I get that all non-Oracle
implementations use v5000 but I don't see how, without feature parity being
a constraint, one can move amongst open source implementations of ZFS. What
am I missing?

Thanks
Thomas
 On Apr 20, 2015 8:22 AM, "Linda Kateley" <lkateley at kateley.com> wrote:

>  Everything beyond v28 is now at 5000. At 5000, feature flags were
> enabled so that you wouldn't have to worry about features in the different
> versions. Those features are held in the pool, so if you import into
> another distro, ZFS will know what features are there, rather than version
> numbers. Features have to be written to not disable pool operations if that
> features isn't enabled on the importing distro.
>
> Once you go up in versions, you can go backwards. The oracle version, last
> time I looked, was at about 32. So once you import into oracle zfs you can
> never go back again. But you can import a free and open pool into oracle
> zfs.
>
> linda
>
> On 4/19/15 8:28 PM, T L wrote:
>
> I get those messages on v28 pools, made with ZFS for Linux or FreeBSD or
> older versions of FreeNAS.
>
> I'm hesitant to move beyond v28, even though I'd like some of the newer
> features, because I am not clear on the compatibility matrix among
> non-Oracle ZFS implementations. Version 28 seems to be the last version
> that all extant ZFS implementations can read. I'd be very willing to give
> up Oracle compatibility but don't want to lock myself out of moving between
> ZFS on Linux and *BSD. If anyone else has thoughts or experience to share
> here, that'd be mist welcome!
>
> Thomas
>  On Apr 19, 2015 6:37 PM, "Clug" <tclug at freakzilla.com> wrote:
>
>> Oh, in case anyone was curious, this is what zpool upgrade returned, so
>> these features for some reason weren't enabled before.
>>
>>     clug at rooster:/home/clug> sudo zpool upgrade
>>     This system supports ZFS pool feature flags.
>>
>>     All pools are formatted using feature flags.
>>
>>
>>     Some supported features are not enabled on the following pools. Once a
>>     feature is enabled the pool may become incompatible with software
>>     that does not support the feature. See zpool-features(5) for details.
>>
>>     POOL  FEATURE
>>     ---------------
>>     media
>>           spacemap_histogram
>>           enabled_txg
>>           hole_birth
>>           extensible_dataset
>>           embedded_data
>>           bookmarks
>>
>> --
>> _______________________________________________
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>> tclug-list at mn-linux.org
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>>
>
>
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>
>
>
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