ZFS

[David Abrahams]

David Abrahams <dave at boost-consulting.com> writes:

> ubuntu at rio.vg writes:
>
>> Is it just me, or does ZFS just sound too good to be true?
>>
>>>From the opensolaris site:
>>
>> "What is ZFS?
>>
>> ZFS is a new kind of filesystem that provides simple administration,
>> transactional semantics, end-to-end data integrity, and immense
>> scalability. ZFS is not an incremental improvement to existing
>> technology; it is a fundamentally new approach to data management. We've
>> blown away 20 years of obsolete assumptions, eliminated complexity at
>> the source, and created a storage system that's actually a pleasure to use."
>>
>> Doesn't that just sound like a scam?  I keep waiting to hear what the
>> downside is...  or maybe I've just been in this business too long and
>> have gotten burned too many times...
>
> If you look around at various blogs about ZFS and RAID-Z you can find
> people taking potshots at it.  Didn't look to me as though any of the
> arguments stood up.  Some things pure improvements on what came before.

Okay, here's one limitation they should be advertising more
prominently: expanding the storage capacity of a RAID-Z system is not
implemented.  As of today, IIUC, you need to "add another RAID-Z",
which means an additional N disks, and storage capacity doesn't flow
smoothly between them (they're like partitions).  

It seems they mostly know how to address that limitation, but there
are some subtle issues left to be worked out.  See the ZFS mailing
list for more details.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com