Put another way, "for RF=2, QUORUM is equivalent to ALL."
On Sun, Nov 28, 2010 at 12:03 PM, David Boxenhorn wrote:
> OK. To sum up: RF=2 and QUORUM are incompatible (if you want to be able to
> take a node down).
>
> Right?
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano
Ok that's a good point i will check - I am not sure.
Sent from my iPhone
On Nov 29, 2010, at 5:53, Tyler Hobbs wrote:
> I'm not familiar with ulimit on RedHat systems, but are you sure you
> have ulimit set correctly? Did you set it to '0' or 'unlimited'? I ask
> because on a Debian system, I
I'm not familiar with ulimit on RedHat systems, but are you sure you
have ulimit set correctly? Did you set it to '0' or 'unlimited'? I ask
because on a Debian system, I get this:
tho...@~ $ ulimit -l
unlimited
Where you said that you got back '0'.
- Tyler
On Sun, Nov 28, 2010 at 1:15 AM, Jaso
Right.
On Sun, Nov 28, 2010 at 1:03 PM, David Boxenhorn wrote:
> OK. To sum up: RF=2 and QUORUM are incompatible (if you want to be able to
> take a node down).
>
> Right?
>
> On Sun, Nov 28, 2010 at 7:59 PM, Jake Luciani wrote:
>
>> I was wrong on this scenario and I'll explain where I was inc
OK. To sum up: RF=2 and QUORUM are incompatible (if you want to be able to
take a node down).
Right?
On Sun, Nov 28, 2010 at 7:59 PM, Jake Luciani wrote:
> I was wrong on this scenario and I'll explain where I was incorrect.
>
> Hints are stored for a downed node but they don't count towards me
On Sun, Nov 28, 2010 at 11:35 AM, Tom Melendez wrote:
> On Sun, Nov 28, 2010 at 12:28 AM, David Boxenhorn wrote:
>> As our launch date approaches, I am getting increasingly nervous about
>> Cassandra tuning. It is a mysterious black art that I haven't mastered even
>> at the low usages that we ha
I was wrong on this scenario and I'll explain where I was incorrect.
Hints are stored for a downed node but they don't count towards meeting a
consistency level.
Let's take 2 scenarios:
RF=6, Nodes=10
If you READ/WRITE with CL.QUORUM you will need 4 alive nodes if one is down
it will still have
On Sun, Nov 28, 2010 at 6:26 PM, David Boxenhorn wrote:
> Hints only happen when a node is unavailable and you are writing with CL.ANY
>
> If you never write with CL.ANY then you can turn off hinted handoff.
Hints happens at any consistency level. But they never helps to
reach the consistency lev
Thank you, Jake. It does... except that in another context you told me:
Hints only happen when a node is unavailable and you are writing with CL.ANY
If you never write with CL.ANY then you can turn off hinted handoff.
How do I reconcile this?
On Sun, Nov 28, 2010 at 7:11 PM, Jake Luciani wrote
Actually you can't. As explained in the wiki page linked:
"A hinted write does NOT count towards ConsistencyLevel requirements
of ONE, QUORUM, or ALL"
For CL.QUORUM, you do need QUORUM *replicas* to be alive to answer
the query. At RF=2, QUORUM=2 so no, you cannot take down any node
down or (some)
If you read/write data with quorum then you can safely take a node down in
this scenario. Subsequent writes will use hinted handoff to be passed to
the node when it comes back up.
More info is here: http://wiki.apache.org/cassandra/HintedHandoff
Does that answer your question?
-Jake
On Sun, N
On Sun, Nov 28, 2010 at 12:28 AM, David Boxenhorn wrote:
> As our launch date approaches, I am getting increasingly nervous about
> Cassandra tuning. It is a mysterious black art that I haven't mastered even
> at the low usages that we have now. I know of a few more things I can do to
> improve th
to me it makes sense that if hinted handoff is off then cassandra cannot
satisfy 2 out of every 3rd writes writes when one of the nodes is down since
this node is the designated node of 2/3 writes.
But I don't remember reading this somewhere. Does hinted handoff affect
David's situation?
(David, di
For the vast majority of my data usage eventual consistency is fine (i.e.
CL=ONE) but I have a small amount of critical data for which I read and
write using CL=QUORUM.
If I have a cluster with 3 nodes and RF=2, and CL=QUORUM does that mean that
a value can be read from or written to any 2 nodes,
If you want to do this, don´t use autoincrementing integers! ;o) Use UUID
instead. (or implement an stand alone id-server that handles autoincrement
savely)
2010/11/28 David Boxenhorn
> As our launch date approaches, I am getting increasingly nervous about
> Cassandra tuning. It is a mysterious
As our launch date approaches, I am getting increasingly nervous about
Cassandra tuning. It is a mysterious black art that I haven't mastered even
at the low usages that we have now. I know of a few more things I can do to
improve things, but how will I know if it is enough? All this is
particularl
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