Re: [gentoo-user] Re: Hard drive storage questions

[Rich Freeman <rich0@gentoo.org>]

On Tue, Apr 28, 2015 at 6:02 PM, walt <w41ter@gmail.com> wrote:
> On 04/28/2015 08:24 AM, Neil Bothwick wrote:
>> On Tue, 28 Apr 2015 17:01:49 +0200, Alan McKinnon wrote:
>
>>> Personally, I like the ZFS approach and do it all in software, catching
>>> errors that RAID misses.
>>
>> The same is also  possible with BTRFS,
>
> I have the impression (without knowing what I'm talking about) that BTRFS
> was created to be just like ZFS, minus the software licensing problems.
>
> Is my impression right or wrong?

Kinda.  Same sort of idea, and the licensing obviously has a big part in it.

The underlying designs are different, which means that when fully
mature each will likely have different pros/cons, which is great since
we can all pick/choose what we need.

The other difference is that ZFS is targeted more at enterprise /
large-scale use, and btrfs is targeted more as a general-purpose
filesystem that you might use on a single-disk PC.  That isn't to say
that either can't be used in either situation, but you can definitely
see where there has been more focus in feature development.  For
example, with zfs you can not only have large pools of drives, but you
can also bind them into smaller redundancy pools.  So, you can have 10
"raid6" arrays bound together which ensures that the scale of rebuilds
is limited while giving you a common pool of space.  On the other
hand, with btrfs you can have a 3-disk raid5 and turn it into a 4-disk
raid5 without having to copy/restore all your data (or you could turn
a 3-disk raid1 into a 4-disk raid5, and even switch halfway so that
half your data is in raid1 mode and half in raid5).  That is the sort
of thing that is handy in a small PC where you don't just have stacks
of disks lying around to build fresh new arrays from, but less
important for a big enterprise SAN where you don't need to add one
disk at a time to a 40-disk storage unit.

I'm sure many features exclusive to either btrfs or zfs will
eventually make their way to the other.  However, their differing
focuses make it likely that some features will mature faster than
others.

And of course btrfs has been taking a fairly long time to mature - it
just doesn't seem like as serious of an enterprise-y project.  But,
neither is Gentoo.  :)

-- 
Rich