[OpenIndiana-discuss] BTRFS for OI, anyone?

[James Carlson]

Hans J. Albertsson wrote:
> I was a bit surprised to see so much near-religious reactions....
> James C is to be commended for his rational answer.

Thanks.  ;-}

Really, it doesn't surprise me too much.

> I was merely trying to find out if
> 
> A: BTRFS would be (easily) doable

Doable, almost certainly not easy.  The VFS and VM bits are quite different.

> B: BTRFS had any advantage at all, at least down the line, years away.
> C: ZFS had any major wins over BTRFS that would make the Q moot.

Each currently has advantages over the other in different departments.
On balance, from what I've seen of BTRFS in Fedora, ZFS has much more
over BTRFS than the reverse.  But that's to be expected; ZFS is much
more mature.

Frankly, I don't expect that to be a useful comparison unless someone is
planning to build a distribution where the default file system is
changed from ZFS to BTRFS.  If someone is going to do that, then there
are a lot of other things that have to change -- the packaging system
and boot sequence all currently depend heavily on ZFS in OpenIndiana.
It'd be a lot of work to change all of that.

Instead, I think the "access to foreign data" argument -- the same
argument that works for JFS, HSFS, NTFS, DOS, and others -- works better
here as a compelling argument for someone (not me ;-}) to do the work.

> I can think of one political/commercial reason for BTRFS: Oracle is
> actually involved, and I guess ZFS technology might seep into BTRFS that
> way, w/o hitting some sort of licensing wall or be too costly.

I'm not sure that's a good argument in the OpenIndiana realm.

Oracle decided to take its ball and go home, so banking on any useful
technology contributions usable for OpenIndiana in the future,
regardless of the vector, is probably not worthwhile.

Sure, someone at Oracle (who owns the "property" rights on ZFS and thus
can relicense bits as they wish) could add some bits from ZFS to BTRFS.
 It's just as likely to suppose that Oracle's marketing of Solaris
depends on having technology differentiators between the "enterprise
class" Solaris and "open source" Linux, and thus crown jewels will never
appear in the latter in any useful form.  Who knows?

In any event, I'd suggest "wait and see."  That means, sure, add BTRFS
support for the "foreign file system access" reasons or even just as a
"proof of concept" but, no, don't bother with a root-on-BTRFS
distribution unless you really like pain.

> P.S.
> I hear some people out there sing the BTRFS' praise, and that is people
> whom I used to trust while at Sun.
> I hear people praise the realtime and/or lowlatency properties of recent
> linuxes, too, and I went ahead and tried, and THAT seemed quite
> reasonable praise.

Compared to what was available on Linux before, BTRFS is indeed "better."

-- 
James Carlson         42.703N 71.076W         <carlsonj at workingcode.com>