RFT: ZFS MFC

[Kip Macy]

Many people are happily running an old pool with the new code. I have
done that in a VM and run load over it just to be certain. The tuning
still applies to i386. On amd64 vm backpressure works, but may
actually be too aggressive - shrinking the ARC in favor of the
inactive pages queue.

Cheers,
Kip


On Tue, May 19, 2009 at 12:54 PM, Dimitry Andric <dimitry at andric.com> wrote:
> 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. :)
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-- 
When bad men combine, the good must associate; else they will fall one
by one, an unpitied sacrifice in a contemptible struggle.

    Edmund Burke