RFT: ZFS MFC

[Dimitry Andric]

On 2009-05-19 19:41, Pete French wrote:
>> http://www.andric.com/freebsd/zfs13/r192269/zfs_mfc-r192269.diff.bz2
> 
> Thanks - am going to gve this a try later. Preseumably if I leave the
> pool at the revision it is currently on then I can revert back easily ?

I'll just repeat what Kip told us, "The standard disclaimers apply.
This has only been lightly tested in a VM. Please do not use it with
data you care about at this time."

That said, zpool(1M) tells:

       zpool upgrade [-V version] -a | pool ...

           Upgrades the given pool to the latest on-disk version. Once this is
           done, the pool will no longer  be  accessible  on  systems  running
           older versions of the software.

and later on:

           -V version    Upgrade  to  the specified version. If the -V flag is
                         not specified, the  pool  is  upgraded  to  the  most
                         recent  version.  This  option  can  only  be used to
                         increase the version number, and only up to the  most
                         recent version supported by this software.

E.g. you can upgrade pools to ZFS v13, but there's no way back.  If you
don't upgrade your pool, it should not destroy anything (but don't count
on it!), but you won't be able to test any new features either...


> Also, is this the version which no longer requires any tuning parameters
> in loader.conf ? That would be extermely interesting!

As far as I know, the tuning stuff still applies, especially for i386.
On my i386 test VM with 1GB RAM, vm.kmem_size is about 163 MiB without
any tuning, while vm.kmem_size_max is about 320 MiB, so you get the warning:

ZFS WARNING: Recommended minimum kmem_size is 512MB; expect unstable behavior.
             Consider tuning vm.kmem_size and vm.kmem_size_max
             in /boot/loader.conf.

So please test, and let us know your findings. :)