Re: [9fans] Petabytes on a budget: JBODs + Linux + JFS

[Eris Discordia <eris.discordia@gmail.com>]

> What I haven't found is a decent, no frills, sata/e-sata enclosure for a
> home system.

Depending on where you are, where you can purchase from, and how much you
want to pay you may be able to get yourself ICY DOCK or Chieftec enclosures
that fit the description. ICY DOCK's 5-bay enclosure seemed a fine choice
to me although somewhat expensive (slightly over 190 USD, I seem to
remember).

--------------------------------------------------------------------------------

Related to the subject of drive reliability:

> A common misconception is that "server-grade" drives fail less frequently
> than consumer-grade drives. Two different, independent studies, by
> Carnegie Mellon University and Google, have shown that failure rates are
> largely independent of the supposed "grade" of the drive.

-- <http://en.wikipedia.org/wiki/RAID>

The paragraph cites this as its source:

--
<http://searchstorage.techtarget.com/magazineFeature/0,296894,sid5_gci1259075,00.html>
(full text available only to registered users; registration is free, which
begs the question of why they've decided to pester penniless readers with
questions their "corporation's" number of employees and IT expenses)

which has derived its content from this study:

<http://www.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html>

I couldn't find the other study, "independent" from this first.



--On Monday, September 21, 2009 15:07 -0700 Bakul Shah
<bakul+plan9@bitblocks.com> wrote:

> On Mon, 21 Sep 2009 16:30:25 EDT erik quanstrom <quanstro@quanstro.net>
> wrote:
>> > > i think the lesson here is don't by cheep drives; if you
>> > > have enterprise drives at 1e-15 error rate, the fail rate
>> > > will be 0.8%.  of course if you don't have a raid, the fail
>> > > rate is 100%.
>> > >
>> > > if that's not acceptable, then use raid 6.
>> >
>> > Hopefully Raid 6 or zfs's raidz2 works well enough with cheap
>> > drives!
>>
>> don't hope.  do the calculations.  or simulate it.
>
> The "hopefully" part was due to power supplies, fans, mobos.
> I can't get hold of their reliability data (not that I have
> tried very hard).  Ignoring that, raidz2 (+ venti) is good
> enough for my use.
>
>> this is a pain in the neck as it's a function of ber,
>> mtbf, rebuild window and number of drives.
>>
>> i found that not having a hot spare can increase
>> your chances of a double failure by an order of
>> magnitude.  the birthday paradox never ceases to
>> amaze.
>
> I plan to replace one disk every 6 to 9 months or so. In a
> 3+2 raidz2 array disks will be swapped out in 2.5 to 3.75
> years in the worst case.  What I haven't found is a decent,
> no frills, sata/e-sata enclosure for a home system.
>