
Jepsen: Distributed Systems Safety Analysis - luu
http://jepsen.io/
======
willchen
I'd be very interested to see RethinkDB analyzed, particularly with the 2.1
release promising high availability through Raft. RethinkDB and Aphyr have
talked about doing Jepsen tests for it, but I'm not sure where that's landed
([https://github.com/rethinkdb/rethinkdb/issues/1493](https://github.com/rethinkdb/rethinkdb/issues/1493)).

~~~
coffeemug
Slava @ Rethink here. Talked to Kyle yesterday, he's doing RethinkDB analysis
next. You should see something in a month or two.

EDIT: don't mean to speak for him though; I hope this is ok.

~~~
Spiritus
Will that be on 2.1 or the upcoming 2.2?

~~~
coffeemug
Probably on the 2.1 branch, but it shouldn't matter too much -- the clustering
codebase is very stable and there aren't any major changes to it between
releases.

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OMGWTF
> Flash plugin missing

> Get the latest Flash player to view this content

No, I won't. This scares me too much:
[https://www.cvedetails.com/vulnerability-
list/vendor_id-53/p...](https://www.cvedetails.com/vulnerability-
list/vendor_id-53/product_id-6761/Adobe-Flash-Player.html)

~~~
annnnd
+1.

Not sure why anyone would want to play video (I guess it's a video? I don't do
Flash either) through Flash nowadays... Isn't it easier and better to just use
HTML video tag?

~~~
biokoda
With live video you don't really have a choice if you want compatibility with
all browsers.

~~~
annnnd
Not really - there is no flash on (most?) mobile devices.

You can also use JS detection. For instance, Youtube uses Flash unless you
allow google.com & googlevideo.com, then it uses HTML video tag. It's not like
it costs you anything to add HTML video tag.

~~~
biokoda
live video. There is no cross browser compatible format for live streaming.

~~~
annnnd
Sorry, missed "live" word. I don't have any (recent) experience with that, so
can't comment on that. But in case of OP's page the video is not live.

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striking
A lot of people are noting their interest in seeing a certain database tested.
Sorry to say so, but:

>> Can you test X next?

> Tests take about a month. I do take suggestions into consideration, but I
> can't promise you anything. Backlog is a few years long at this point.

(from [https://aphyr.com/about](https://aphyr.com/about))

~~~
willchen
Fair point. For RethinkDB, I think there's a good business case for getting it
tested sooner than later (on both sides). For aphyr who's leaving Stripe, I
think it would be reasonable for RethinkDB to compensate him for an unbiased
study, given that they have $12M+ in funding. A positive report could generate
a lot of attention for RethinkDB and give confidence to larger enterprises who
are very hesitant of trying anything remotely "new" or "experimental" in the
DB space.

~~~
rdtsc
> A positive report could generate a lot of attention for RethinkDB

A negative report could generate the opposite though. Are they ready to bet
the new $12M+ on that?

Then also if they compensate him, not sure how unbiased others will think (and
we are talking about perception here) the study will be.

~~~
nosequel
Up to this point, nothing in Aphyr's history has suggested he'd be a biased
tester. When he tested Riak, he was invited to Ricon to give the results for
the world to see live. Much of the Basho engineers at the time were personal
friends of his. As you know if you read that analysis, Aphyr held back
nothing.

Right now I'd trust Aphyr more than any other analyst, consultant, or full-
time employee (with employment to lose) to give truly impartial judgement.

~~~
rdtsc
It is about perception. I think he's unbiased, you do as well it seems. But to
others it might look biased. That was my point.

~~~
nosequel
Oh yeah, I'm with you completely. I trust that he will stay impartial, and I
hope that vendors allow him the freedom to write as he has in the past so that
all appearances reflect what I believe to be is the reality.

------
headcanon
I wonder if Carly Rae Jepsen is aware of the legacy of her song in the
software world...

~~~
TeMPOraL
Somebody call her maybe?

------
JoelJacobson
Why isn't PostgreSQL in the list on the first page? It is in the [blog posts]
page though.

I would love to see the multixact data corruption problems introduced in 9.3
analyzed, and see if he can verify them to be solved in the latest version.

~~~
amitlan
Not quite sure whether something like multixact data corruption is symptomatic
of the kind of underlying issues in database system implementations that
Jepsen is after. I may be wrong though.

~~~
Jweb_Guru
It wasn't. It's also rather difficult to trigger. I have no doubt that aphyr
could do stuff like that if he so chose, but I think pounding on getting a
reproducible test case for Postgres's subtle serializable bug would be more
his speed.

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jhasse
Please make the title more verbose.

~~~
885895
Either OP or mods have corrected the title now.

------
eddd
I really dig the Riak test. One of the best comparison of LWW and CRDT. Also
very good conclusion, tl; dr: If you don't use idempotent writes, you are
going to have bad time.

~~~
rspeer
Well, Last Write Wins is idempotent too. I would say the conclusion is that
it's important that your writes are commutative and associative.

(The problem, then, is that data structures with all these properties are hard
to find.)

------
felixgallo
On a human note: Kyle is brave as fuck for stepping out into the black unknown
yawning abyss to try to do this under his own banner. Bravo, Kyle, and may you
find incredible success.

~~~
mdaniel
The other side to that coin is that these reports are always in the top of the
front page of HN, and likely on Reddit, also. They are popular because they
are great, and I don't want to live in a world where people can't be paid
fairly to do _great_ things.

------
doomrobo
Was Jespen developed at Stripe? If so, how can aphyr get the rights to use
Jespen for individual contracting work?

~~~
masklinn
Jepsen was developed by aphyr/kyle. Stripe hired him early this year (January
2015[0]), I understand in part to support his Jepsen work, but he's been
working on it since 2013[1].

So to answer the question, no Jepsen was not "developed at stripe" though part
of its development probably happened there.

[0]
[https://twitter.com/avibryant/status/561315494204952579](https://twitter.com/avibryant/status/561315494204952579)

[1] [https://aphyr.com/posts/281-call-me-maybe-carly-rae-
jepsen-a...](https://aphyr.com/posts/281-call-me-maybe-carly-rae-jepsen-and-
the-perils-of-network-partitions)

------
MCRed
I really would like to see Couchbase analyzed... and for aphyr to marry me.

~~~
mbesto
I'm actually genuinely interested in that as well (Not the marrying part),
especially considering aphyr and Damien Katz went at it about a year ago:
[https://twitter.com/damienkatz/status/527588456747499520](https://twitter.com/damienkatz/status/527588456747499520)

~~~
augustl
What I find really interesting is that while it appears to me that Katz has
very sparse knowledge of databases, he has still managed to create one or two
of them, and successfully run a company that sells one. I don't like the
thought I had next, but: perhaps knowing about consensus algos and papers
actually doesn't matter?

~~~
DomreiRoam
Depends on the problem you want to solve. CouchDB is a very good document
database when you have more read than write and when writer are mostly writing
on different documents. If I understand correctly replication conflict
resolution is up to the application. So knowing about consensus algo is
unnecessary for CouchDB because he doesn't support it.

I think it's smart to know a little about the literature; enough to know what
battle you don't want to fight. It is not smart to try to develop an engine on
the basis that it will need to beat the law of thermodynamic to be possible.

But also, “They did not know it was impossible so they did it”, Mark Twain

~~~
krugster
FWIW, Couchbase != CouchDB: [http://www.couchbase.com/couchbase-vs-
couchdb](http://www.couchbase.com/couchbase-vs-couchdb)

+1 For Jepson on Couchbase

------
votemedown
The only thing that passes Jespen: vim.

