
Hard Drive Reliability Stats for Q1 2015 - ars
https://www.backblaze.com/blog/best-hard-drive/
======
madaxe_again
The bit about the ST3000DM001 is fascinating - they've a longer article on it
at [https://www.backblaze.com/blog/3tb-hard-drive-
failure](https://www.backblaze.com/blog/3tb-hard-drive-failure) \- I have had
four (out of the four I bought - two internal, two "shucked") of these die on
me over the years, on the first occasion simultaneously in a raid-5 array that
I'd just downloaded several TB of irreplaceable video to from SD cards. Now at
least I know why.

~~~
sliverstorm
SD cards are pretty easy to recover media from, if you haven't overwritten
them.

Also, I'm a bit surprised by their topology. Reading the bit about the 3TB
drives, it sounds like three drive failures in their raid5 array would result
in lost customer data.

I hope they have a 2nd line of defense, e.g. tapes. One company I used to work
for ran into sufficient failures (particularly of the living-dead variety,
where a second drive fails during rebuild or after reboot) they made tapes the
3rd line of defense, and maintained two copies of all data at the cluster
level, so that the total failure of an entire machine was acceptable.

~~~
thaumaturgy
"A Backblaze Vault is comprised of 20 Storage Pods, with the data evenly
spread across all 20 pods. ... Drives in the same drive position in each of
the 20 Storage Pods are grouped together into a storage unit we call a “tome”.
... Every file uploaded to a Vault is broken into pieces before being stored.
Each of those pieces is called a “shard”. ... Each file is stored as 20
shards: 17 data shards and 3 parity shards. Because those shards are
distributed across 20 storage pods in 20 cabinets, the Vault is resilient to
the failure of a storage pod, or even a power loss to an entire cabinet."

From [https://www.backblaze.com/blog/vault-cloud-storage-
architect...](https://www.backblaze.com/blog/vault-cloud-storage-
architecture/), which is well worth taking a few minutes to read. Their
approach to data resiliency is pretty neat and full of the kind of common-
sense reasoning that warms the very bottoms of my ol' sysadmin's heart ("use
simple parts" and "build the tools you need to run your infrastructure", among
others).

~~~
atYevP
Yev from Backblaze here -> Glad you like the build! We have more fun things
we're working on in that regard ;-)

------
userbinator
I thought it was the same article I'd seen before since I've seen this URL
appear on HN before at
[https://news.ycombinator.com/item?id=8923535](https://news.ycombinator.com/item?id=8923535),
but apparently it's not. Only the small "May 21st, 2015" text in the article
is any indication.

I think they really need to put a date in the URL and not just overwrite the
previous version, so we can see how things change over time.

Edit: in fact they had a nice bargraph of the failure rates by drive model in
their previous post, but it's gone now. Fortunately someone seems to have
archived a copy of it here:
[http://thetrendythings.com/read/28144](http://thetrendythings.com/read/28144)

~~~
theandrewbailey
Some of the previous articles are still up:

[https://www.backblaze.com/blog/best-hard-
drive-q4-2014/](https://www.backblaze.com/blog/best-hard-drive-q4-2014/)

[https://www.backblaze.com/blog/hard-drive-reliability-
update...](https://www.backblaze.com/blog/hard-drive-reliability-update-
september-2014/)

[https://www.backblaze.com/blog/what-hard-drive-should-i-
buy/](https://www.backblaze.com/blog/what-hard-drive-should-i-buy/)

[https://www.backblaze.com/blog/how-long-do-disk-drives-
last/](https://www.backblaze.com/blog/how-long-do-disk-drives-last/)

You can also sift through the data yourself: [https://www.backblaze.com/hard-
drive-test-data.html](https://www.backblaze.com/hard-drive-test-data.html)

------
stephengillie
Are these consumer drives being used in an industrial setting?

I'm surprised to see such high AFR from Seagate and WD. These brands have had
decades of well-deserved loyalty and trust, and I'd never suspected some of
their drives have such high failure rates.

Why are HGST's AFR numbers so much more preferable?

~~~
theandrewbailey
HGST was originally IBM's hard drive division. They probably have inherited
much of the reliability secrets that the other manufacturers never bothered
with for their consumer class drives (which Backblaze uses). Either that, or
they learned a lot of stuff with the "DeathStar" model[0].

[https://en.wikipedia.org/wiki/Hitachi_Deskstar#IBM_Deskstar_...](https://en.wikipedia.org/wiki/Hitachi_Deskstar#IBM_Deskstar_75GXP_failures)

~~~
frik
Yes, but nowadays HGST is no more. The company has been bought by WD, the 2.5"
and smaller HDDs are now part of Western Digital. The 3.5" HDDs are now
Toshiba due regulatory requirements.

[http://en.wikipedia.org/wiki/HGST](http://en.wikipedia.org/wiki/HGST)

~~~
theandrewbailey
A surprising amount of industry consolidation happened after the Thailand
floods a few years ago. There's what, 3 hard drive manufacturers left!?

[https://en.wikipedia.org/wiki/File:Diagram_of_Hard_Disk_Driv...](https://en.wikipedia.org/wiki/File:Diagram_of_Hard_Disk_Drive_Manufacturer_Consolidation.svg)

------
Rexxar
What is the formula used for confidence interval ? "0.0%-106.9%" interval for
low numbers is somewhat disturbing. What approximation cause this problem ?

~~~
wtallis
The 106.9% isn't a problem of mathematics; it just means an average of more
than one failure per drive per year, or alternatively an average lifespan of
less than one year. It comes from the fact that they've only had those models
in service for a very short time, and so they can only constrain the lifetime
through the same reasoning used to estimate a MTBF of multiple years with less
than a year of testing. With zero failures so far, it's obvious why the bottom
of the confidence interval is at 0%.

------
frik
Please rename the HGST drives. There are only Seagate, Western Digital and
Toshiba - HGST is no more.

Hitachi Global Storage Technologies (HGST) is now a wholly owned subsidiary of
Western Digital! To address the requirements of regulatory agencies, in May
2012 WD divested to Toshiba assets that enabled Toshiba to manufacture and
sell 3.5-inch hard drives for the desktop and consumer electronics markets. So
all HGST 3.5" HDDs are now Toshiba, whereas the HGST 2.5" and smaller HDDs
from Western Digital.

See: [http://en.wikipedia.org/wiki/HGST](http://en.wikipedia.org/wiki/HGST)

~~~
thaumaturgy
This comes across as a pet peeve. If the drives are branded, marketed, and
sold as HGST, then they are HGST drives. Even if Yev is wrong, it's possible
that WD or Toshiba are maintaining HGST drives to different specifications or
QA standards.

And I don't think Yev's wrong, I'm pretty sure I remember reading/hearing the
same, and [http://www.zdnet.com/article/western-digitals-hgst-
cuts-500-...](http://www.zdnet.com/article/western-digitals-hgst-
cuts-500-singapore-jobs-shifts-production-to-thailand/) also suggests that WD
is maintaining HGST as a separate entity.

Calling HGST drives Western Digital or Toshiba would be more confusing, not
less.

~~~
frik
Either call them Hitachi or HGST or Toshiba. But as HGST still exists as a
brand name of Western Digital and new HGST drives are either 2.5 or don't
resemble the old ones mentioned in the statistics, it get's quite confusing -
as the statistics is often used as a buyer guide. Adding a remark somewhere on
his article would help to avoid the confusion.

