Re: [gentoo-user] OT: btrfs raid 5/6

[Richard Bradfield]

On Wed, Dec 06, 2017 at 06:35:10PM -0500, Rich Freeman wrote:
>On Wed, Dec 6, 2017 at 6:28 PM, Frank Steinmetzger <Warp_7@×××.de> wrote:
>>
>> I don’t really care about performance. It’s a simple media archive powered
>> by the cheapest Haswell Celeron I could get (with 16 Gigs of ECC RAM though
>> ^^). Sorry if I more or less stole the thread, but this is almost the same
>> topic. I could use a nudge in either direction. My workplace’s storage
>> comprises many 2× mirrors, but I am not a company and I am capped at four
>> bays.
>>
>> So, Do you have any input for me before I fetch the dice?
>>
>
>IMO the cost savings for parity RAID trumps everything unless money
>just isn't a factor.
>
>Now, with ZFS it is frustrating because arrays are relatively
>inflexible when it comes to expansion, though that applies to all
>types of arrays. That is one major advantage of btrfs (and mdadm) over
>zfs.  I hear they're working on that, but in general there are a lot
>of things in zfs that are more static compared to btrfs.
>
>--
>Rich
>

When planning for ZFS pools, at least for home use, it's worth thinking
about your usage pattern, and if you'll need to expand the pool before
the lifetime of the drives rolls around.

I incorporated ZFS' expansion inflexibility into my planned
maintenance/servicing budget. I started out with 4x 2TB disks, limited
to those 4 bays as you are, but planned to replace those drives after a
period of 3-4 years.

By the time the first of my drives began to show SMART errors, the price
of a 3TB drive had dropped to what I had paid for the 2TB models, so I
bought another set and did a rolling upgrade, bringing the pool up to
6TB.

I expect I'll do the same thing late next year, I wonder if 4TB will be
the sweet spot, or if I might be able to get something larger.

-- 
Richard