[nycbug-talk] Fwd: Re: OpenSolaris dead

Charles Sprickman spork at bway.net
Tue Aug 17 00:40:52 EDT 2010

On Mon, 16 Aug 2010, Jason Dixon wrote:

> (Sorry for the ill-formatted version, resending)
>> On Mon, Aug 16, 2010 at 9:48 PM, George Rosamond
>> <george at ceetonetechnology.com <mailto:george at ceetonetechnology.com>>
> wrote:
>>      I have not read the whole document, but certainly there's open
>>      questions about ZFS (which I have heard is a full, irrevocable
>>      fork), dtrace, etc.
>> If its a full fork, and non Sun/Oracle employees have been porting it to
>> FreeBSD, whats the big deal there?
>>      I'd assume that there's a wide audience of developers and users who
>>      will be looking for a new home. . .
>> Solaris was only open source for a few years. Other than those that
>> jumped on the Solaris band wagon after the open sourcing, I'm not sure
>> who feels they are in need of a new home. Also, thats only a big deal
>> for kernel and some core userland developers.
> You're vastly underestimating the number of Solaris/OpenSolaris users and
> companies looking for an exit path.  They were enticed into OpenSolaris
> and SXCE thanks to exciting projects like Crossbow and bleeding-edge
> features in ZFS.  Now many of their systems are backwards-compatible with
> anything that Oracle will support now or in the future.

I've noticed that the Linux folks are also quite excited about this - it's 
an opportunity to push btrfs pretty hard.  I do think many of them are 
overestimating how close to production use it is though.

There is also quite a bit of talk on more linux-centric boards about zfs 
being a poor performer compared to just about any linux fx paired with 
lvm/md.  This I'm not so sure about - Phoronix seems to be the go-to place 
now for benchmarks, and some of their methods are... odd to say the least.

Slightly OT, I'm looking for a benchmark that deals more with iops rather 
than throughput and has a fairly simple output - just something that 
sweeps through various sizes and then spits out a summary of how many io 
operations/second it recorded.

>> Don't get me wrong, things are getting interesting from here, but I
>> don't think its going to be that big of a deal in retrospect. The only
>> big deal outcome is if Oracle ends up re open sourcing it. If Oracle
>> increases Solaris's popularity after close sourcing it, it proves Oracle
>> is a better business than Sun, not that Close source is a better
>> business model than Open Source. You have Linux and the BSDs proving the
>> viability of Open Source OS development.
> This is not a closed-versus-open source issue.  For OpenSolaris users,
> it's having a predictable support path and roadmap.  For the BSD
> community (in particular, FreeBSD), it's an opportunity to a) embrace new
> users and b) show off the capabilities and innovation available within
> BSD.
> I've had countless discussions with other Solaris users over the last few
> months.  FreeBSD is a popular topic of discussion, particularly as a
> favored alternative to Linux.  But there are still a lot of questions
> these folks have, and I think this is a good time to reach out and
> demonstrate why BSD software (and the associated communities) are a great
> option to wayward Solaris users.

I am somewhat concerned about FreeBSD in general and specifically what the 
plans are there for ZFS (both in general and  the impact of oracle perhaps 
not ever releasing any additional code).  I've seen lots of folks 
experimenting with FreeBSD just for ZFS, many that have never given 
FreeBSD a second thought.  They seem to avoid the official mailing lists 
and work with each other to tune and debug things either on the FBSD 
forums or other general tech forums, so I don't know how aware the core 
group of FBSD developers are of this growing group of users coming to FBSD 
strictly for ZFS (and finding a pretty decent OS to go along with it).

It seems like even with ZFS now being offically labelled as 
production-ready on FBSD, there's very little documentation popping up, 
and the few people that understand the internals are not really available 
to help out those who want to document it.  The classic case is the whole 
issue of running ZFS on i386 - tuning it to not panic is not easy, and the 
manpages are still just straight rips from open solaris - there's no 
FreeBSD-specific info in there.  The wiki (http://wiki.freebsd.org/ZFS) is 
somewhat dated and does not really explain the i386 tuning issue well. 
It's also not open to editing.  There are a few tricks to getting i386 
stable, but it's not readily apparent.  The biggest hint I found (and I've 
heard this may have changed) is that the arc_max value is NOT a hard 
limit, but a high water mark where a thread to flush the arc to disk kicks 
off.  On slower/older hardware with unpredictable disk load, the time it 
takes for that thread to do what it needs to can fall behind the rate at 
which some process is writing data that lands in the ARC.  When that 
happens, boom!  I had much better luck tuning this once I realized that I 
could routinely load the box in a way that the arc could grow to double 
it's "max" size.  In some cases that meant just going with better hardware 
(and 64-bit, where zfs is very stable), and in others it could be worked 
around by setting the ARC max very low - in essence giving the flush to 
disk thread a little bit of a head start.

There's also the issue of sysinstall, especially if you want to do a zfs 
on root setup.

And there's currently a show-stopper bug in 8.1 where a raidz1 array 
that's degraded cannot be booted from because some regression was 
introduced into the zfs bootloader.

Anyhow, yeah this could be a great opportunity, but I think there has to 
be some sort of meeting of whoever is "in charge" of the FreeBSD project 
to get some kind of leadership/management going on this front.  Docs would 
actually be an excellent start, but beyond that I think there needs to be 
more ownership of ZFS amongst the development team - right now I think 
there's essentially two people involved in what could be one of the 
biggest features FreeBSD has ever introduced.

BTW, if anyone wants to start a general zfs thread, I love to talk about 
it. :)  I'm in the midst of migrating a bunch of 4.11 boxes to 8.1 w/zfs 
on root.


> -- 
> Jason Dixon
> DixonGroup Consulting
> http://www.dixongroup.net
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