Re: OT - was Hammer or ZFS based backup, encryption

[Jeremy Chadwick <jdc@xxxxxxxxxxxx>]

On Sun, Feb 22, 2009 at 11:59:57AM +1100, Dmitri Nikulin wrote:
> On Sun, Feb 22, 2009 at 10:34 AM, Bill Hacker <wbh@conducive.org> wrote:
> > Hopefully more 'good stuff' will be ported out of Solaris before it hits the
> > 'too costly vs the alternatives' wall and is orphaned.
> 
> Btrfs has been merged into mainline Linux now, and although it's
> pretty far behind ZFS in completeness at the moment, it represents a
> far greater degree of flexibility and power. In a couple of years when
> it's stable and user friendly, high-end storage solutions will move
> back to Linux, after having given Sun a lot of contracts due
> specifically to ZFS.

The fact that btrfs offers grow/shrink capability puts it ahead of ZFS
with regards to home users who desire a NAS.  I can't stress this point
enough.  ZFS's lack of this capability limits its scope.  As it stands
now, if you replace a disk with a larger one, you have to go through
this extremely fun process to make use of the new space available:

- Offload all of your data somewhere (read: not "zfs export"); rsync
  is usually what people end up using -- if you have multiple ZFS
  filesystems, this can take some time
- zpool destroy
- zpool create
- zfs create

And if you add a new disk to the system, it's impossible to add that
disk to the existing pool -- you can, of course, create an entirely
new zpool which uses that disk, but that has nothing to do with the
existing zpool.  So you get to do the above dance.

I'll also point out that ZFS on FreeBSD (at least 7.x) performs very
differently than on Solaris 10.  We use Solaris 10 x86 + ZFS at my
workplace, and the overall usability of the system during heavy disk I/O
is much more refined (read: smooth) than on FreeBSD.  It's interesting
to do something like "zpool iostat 1" on FreeBSD compared to Solaris 10;
FreeBSD will show massive write bursts (e.g. 0MB, 0MB, 0MB, 70MB, 0MB,
0MB, 0MB, 67MB, etc.), while Solaris behaves more appropriately (50MB,
60MB, 70MB, 40MB, etc.).  "zpool scrub" is a great way to test this.

> So Sun's options are to GPL/BSD ZFS and hope it gets used more so they
> have some relevance left, or somehow attempt to be able to compete
> with Linux and BSD's development pace and massive head start. I think
> it's pretty clear where that'll go.

I'm a little surprised to see BSD put alongside Linux when it comes to
"development pace".  Fact of the matter is, Linux wins when it comes to
pace/speed of development -- they have more kernel folks, more eyes,
a significantly larger user-base for testing, and absurd amounts of
commercial backing/support from actual hardware vendors.  Sun has
some of this, but it's gotten worse (IMHO) since they started going
the x86 route.  BSD often trails behind Linux by 3-5 years.

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |