Ø I keep hearing that the minimum number of Cassandra nodes required to
achieve Quorum consensus is 4 I wonder why not 3? In fact, many container
deployments by default seem to deploy 4 nodes. Can anyone shine some light on
this?
I think it may be due to the following (note : I am assuming, he
Hi,
A hint : depending on your data set size + your request rate per second, 8 GB
of RAM may be too low.
And then, CPU might be high due to too frequent GC.
More RAM may bring:
· More space for OS FS to cache the SSTable files in memory.
· A greater heap size, and then, less fr
Hi Amlan,
We have the same pb with Cassandra 2.1.5.
I have no hint (yet) to follow.
Did you found the root of this pb ?
Thanks.
Regards,
Dominique
[@@ THALES GROUP INTERNAL @@]
De : Amlan Roy [mailto:amlan@cleartrip.com]
Envoyé : mercredi 1 juillet 2015 12:46
À : user@cassandra.apache.o
21, 2015 at 5:37 PM, DE VITO Dominique
mailto:dominique.dev...@thalesgroup.com>>
wrote:
Hi Amlan,
We have the same pb with Cassandra 2.1.5.
I have no hint (yet) to follow.
Did you found the root of this pb ?
Thanks.
Regards,
Dominique
[@@ THALES GROUP INTERNAL @@]
De : Amlan
Hi,
Is there any info about running C* on top of a NAS storage, well, a RAIN
storage (to be precise) in fact ?
I expect C* to run on top of a RAIN like on top of a high-end SAN: that is,
with a drop (-50%) in performance.
Any return available ?
Thanks.
Regards,
Dominique
mars 2016 17:56
À : user@cassandra.apache.org
Objet : Re: Cassandra runing on top of NAS (RAIN storage) !?? anyone ?
Don't do it
On Fri, Mar 4, 2016 at 8:39 AM DE VITO Dominique
mailto:dominique.dev...@thalesgroup.com>>
wrote:
Hi,
Is there any info about running C* on top of a NAS st
Hi,
Let's imagine a cluster of 6 nodes, 5 on rack1 and 1 on rack2.
With RF=3 and NetworkTopologyStrategy, "The first replica per data center is
placed according to the partitioner (same as with SimpleStrategy). Additional
replicas in the same data center are then determined by walking the ring
> > De : Tyler Hobbs [mailto:ty...@datastax.com]
> > Envoyé : mardi 16 octobre 2012 17:04
> > À : user@cassandra.apache.org
> > Objet : Re: what happens while node is bootstrapping?
> >
> > On Mon, Oct 15, 2012 at 3:50 PM, Andrey Ilinykh wrote:
> > Does it mean that during bootstrapping process o
> > De : Tyler Hobbs [mailto:ty...@datastax.com]
> > Envoyé : mardi 16 octobre 2012 17:04
> > À : user@cassandra.apache.org
> > Objet : Re: what happens while node is bootstrapping?
> >
> > On Mon, Oct 15, 2012 at 3:50 PM, Andrey Ilinykh wrote:
> > Does it mean that during bootstrapping process o
Hi Everton,
AFAIK, the pb is not forcing data to a specific node, but forcing some kind of
data locality.
There is things into cql to do it: you define a composite key (K1, K2), and K1
part is used as a rowkey and K2 is used within column name. So, all rows with
same K1 are on the same node.
ial application. How should I choose the K1 part
to forcing a given object to go to a node?
2013/1/3 DE VITO Dominique
mailto:dominique.dev...@thalesgroup.com>>
Hi Everton,
AFAIK, the pb is not forcing data to a specific node, but forcing some kind of
data locality.
There is things into cql
Hi,
>From time to time, I have seen discussed in ML the 'disk_access_mode' property.
But...
- this property is not mentionned in v1.1 full doc PDF (it's only mentionned
under another name 'DiskAccessMode' => so doing CTRL-F for 'disk_access_mode'
finds nothing)
- this property is not in cassand
property to your cassandra.yaml and set it to
standard to disable memory mapped access, it will work. It's the same thing for
the auto_bootstrap parameter and some other property like these two, they are
not written in the conf anymore but still read if they exist.
Alain
201
Hi,
Is "nodetool repair" only usable if the node to repair has a valid (=
up-to-date with its neighbors) schema?
If the data records are completely broken on a node with , is it valid
to clean the (data) records and to execute replace_token= on the *same*
node?
Thanks.
Regards,
Dominique
Hi,
Edward Capriolo described in his Cassandra book a faster way [1] to start new
nodes if the cluster size doubles, from N to 2 *N.
It's about splitting in 2 parts each token range taken in charge, after the
split, with 2 nodes: the existing one, and a new one. And for starting a new
node, on
d from the second edition. It still likely
works except when using counters.
Edward
On Tue, Jan 8, 2013 at 7:27 AM, DE VITO Dominique
mailto:dominique.dev...@thalesgroup.com>>
wrote:
Hi,
Edward Capriolo described in his Cassandra book a faster way [1] to start new
nodes if the clust
Is Cassandra 1.1 Row Level Isolation (a kind of batch-like) related to
"traditional" batch_mutate or atomic_batch_mutate Thrift API ?
Thanks for the answer.
Dominique
De : Sylvain Lebresne [mailto:sylv...@datastax.com]
Envoyé : mardi 12 février 2013 10:19
À : user@cassandra.apache.org
Objet :
Hi,
About BATCH, the Apache doc
https://cassandra.apache.org/doc/latest/cql/dml.html?highlight=atomicity says :
"The BATCH statement group multiple modification statements (insertions/updates
and deletions) into a single statement. It serves several purposes:
...
All updates in a BATCH belongin
s.
Dominique
[@@ THALES GROUP INTERNAL @@]
De : DuyHai Doan [mailto:doanduy...@gmail.com]
Envoyé : vendredi 29 septembre 2017 17:10
À : user
Objet : Re: understanding batch atomicity
All updates here means all mutations == INSERT/UPDATE or DELETE
On Fri, Sep 29, 2017 at 5:07 PM, DE V
Hi,
I have not seen any available cmd like "nodetool showparameters" to show loaded
cassandra.yaml parameters of one node (to display them remotely, or to check if
loaded parameters are the ones of the "cassandra.yaml").
Does anyone know if there is a cmd to display those parameters (I don't th
Hi,
While reading the OpsCenter 5.1 docs, it looks like OpsCenter can't work if
Cassandra does not provide a Thrift interface (see [1] below).
Is it really the case ?
At first sight, it sounded weird to me, as CQL 3 is provided for months.
Just to know, is a OpsCenter future version, not relyi
Hi Carlos,
Different possibilities (to log slow queries).
1) A probabilistic way to catch slow queries (probabilistic, but with
detailed info) => look for “nodetool settraceprobability” like in
http://www.datastax.com/dev/blog/advanced-request-tracing-in-cassandra-1-2
2) Catch slow
Hi,
One valuable (IMHO) entry point is : « Guide to Cassandra Thread Pools »
http://blackbird.io/guide-to-cassandra-thread-pools
Take a look.
Regards,
Dominique
De : pushdlim...@gmail.com [mailto:pushdlim...@gmail.com] De la part de Saurabh
Chandolia
Envoyé : vendredi 19 juin 2015 11:42
À : u
Hi,
I have the following use case:
If I update a data on DC1, I just want apps "connected-first" to DC2 to be
informed when this data is available on DC2 after replication.
When using Thrift, one way could be to modify CassandraServer class, to send
notification to apps according to data coming
> On 03/10/2014 07:49 AM, DE VITO Dominique wrote:
> > If I update a data on DC1, I just want apps "connected-first" to DC2
> > to be informed when this data is available on DC2 after replication.
>
> If I run a SELECT, I'm going to receive the latest data
?
Thanks.
Dominique
On Mon, Mar 10, 2014 at 10:06 AM, DE VITO Dominique
wrote:
> On 03/10/2014 07:49 AM, DE VITO Dominique wrote:
> > If I update a data on DC1, I just want apps "connected-first" to DC2
> > to be informed when this data is available on DC2 after rep
l&ei=Hd4dU-7IGOTq0wHT-YHQCw&usg=AFQjCNELJe3hmp_gJWXih91S1CL2f4KLtQ&sig2=xJ5h_7FqX-qZ6iVgXwpr-g&bvm=bv.62578216,d.dmQ>
patch because triggers are currently only called on batch_mutate and will fail
if called on insert.
On Mon, Mar 10, 2014 at 10:50 AM, DE VITO Dominique
mailto:dominiqu
Hi,
> -Message d'origine-
> De : ssiv...@gmail.com [mailto:ssiv...@gmail.com]
> Envoyé : jeudi 27 mars 2014 10:41
> À : user@cassandra.apache.org
> Objet : Re: Which hector version is suitable for cassandra 2.0.6 ?
>
> On 03/27/2014 12:23 PM, user 01 wrote:
> > Btw both Hector & Datastax
Hi,
Nodetool tpstats gives 2 lines for anti-entropy: one for AntiEntropySessions
and one for AntiEntropyStage.
What is the difference ?
a) Is "AntiEntropySessions" for counting repairs on a node acting as a
primary node (the target node for repair) ?
And is "AntiEntropyStage" for countin
Hi,
The instruction < CLibrary.tryMlockall(); > is called at the very beginning of
the setup() Cassandra method.
So, the heap space is memlocked in memory (if OS rights are set).
"mlockall()" is called with "MCL_CURRENT" : "MCL_CURRENT Lock all pages
currently mapped into the process's address
Robert,
Thanks for your explanation!
Regards,
Dominique
De : Robert Coli [mailto:rc...@eventbrite.com]
Envoyé : vendredi 1 août 2014 19:50
À : user@cassandra.apache.org
Objet : Re: question about commitlog segments and memlocking
On Fri, Aug 1, 2014 at 2:53 AM, DE VITO Dominique
Hi,
My understanding is that NetworkTopologyStrategy does NOT play well with
vnodes, due to:
* Vnode => tokens are (usually) randomly generated (AFAIK)
* NetworkTopologyStrategy => required carefully choosen tokens for all
nodes in order to not to get a VERY unbalanced ring lik
licas would be distributed across the rest of
the machines.
http://www.datastax.com/documentation/cassandra/2.0/cassandra/architecture/architectureDataDistributeReplication_c.html
On Tue, Aug 5, 2014 at 8:19 AM, DE VITO Dominique
wrote:
> Hi,
>
>
>
> My understanding is that NetworkTopologyStra
improbable that the ring will be imbalanced.
On Tue, Aug 5, 2014 at 8:57 AM, DE VITO Dominique
wrote:
> First, thanks for your answer.
>
>> This is incorrect. Network Topology w/ Vnodes will be fine, assuming you've
>> got RF= # of racks.
>
> IMHO, it'
ti-data-center-replication-in-nosql-databases/<http://planetcassandra.org/multi-data-center-replication-in-nosql-databases/>
The last section may be of interest for you
Le 5 août 2014 18:14, "DE VITO Dominique"
mailto:dominique.dev...@thalesgroup.com>> a
écrit :
> Jonathan wr
Hi,
I want to use Cassandra for (fast) unit testing with a small number of data.
So, I imagined the Cassandra embedded server I plan to use would start faster
and would be more portable (because no file path depending on OS), without disk
storage mode (so, diskless if you want).
Is there some
Hi,
I have tried few experiments with Composite (first, as columns, and next, as
rows).
I have followed the paths described by
http://www.datastax.com/dev/blog/introduction-to-composite-columns-part-1
My composite is (UTF8, UTF8): (folderId, filename)
And I have inserted for all tests, the foll
Hi,
Let's suppose a column (name+value) is cached in memory, with timestamp T.
1) An update, for this column, arrives with exactly the *same* timestamp, and
the *same* value.
Is the commitlog updated ?
2) An update, for this column, arrives with a timestamp < T.
Is the commitlog updated ?
Than
Hi,
We have defined a CF with a composite row key that sounds like (folder id, doc
id).
For our app, one very common pattern is accessing, through one ui action, some
bunch of data with the following row keys: (id, id_1), (id, id_2), (id, id_3)...
So, multiple rows are accessed, but all row key
When the coordinator node receives a batch_mutate with different N row keys
(for different CF) :
a) does it treat them as N independent requests to replicas, or
b) does the coordinator node split the the initial batch_mutate into M
batch_mutate (M <= N) according to rowkeys ?
Thanks,
Dominique
Hi,
I have a use case that sounds like storing data associated with files. So, I
store them with the CF:
rowkey = (folder_id, file_id)
colname = property name (about the file corresponding to file_id)
colvalue = property value
And I have CF for "manual" indexing:
rowkey = (folder_id, indexed val
spread the rows and consider how they grow over
time.
You can send updates for multiple rows in the same batch mutation.
Hope that helps.
-
Aaron Morton
Freelance Cassandra Consultant
New Zealand
@aaronmorton
http://www.thelastpickle.com
On 9/04/2013, at 3:57 AM, DE VITO Domi
When the coordinator node receives a batch_mutate for __one__ row key
associated with different mutations for different CF :
Is it true the coordinator node treats them as __independent__
communications/requests to replicas (even if in that case, the replicas are the
same for every request) ?
Hi,
We are created a new partitioner that groups some rows with **different** row
keys on the same replicas.
But neither the batch_mutate, or the multiget_slice are able to take
opportunity of this partitioner-defined placement to vectorize/batch
communications between the coordinator and the
; I am not very sure if it's related to my topic
Thanks.
Dominique
>
> Cheers
>
>
> -----
> Aaron Morton
> Freelance Cassandra Consultant
> New Zealand
>
> @aaronmorton
> http://www.thelastpickle.com
On 27/04/2013, at 4:04 AM, DE VITO Dominique
ma
to go...
Regards.
Dominique
> Cheers
>
> -
> Aaron Morton
> Freelance Cassandra Consultant
> New Zealand
>
> @aaronmorton
> http://www.thelastpickle.com
On 7/05/2013, at 5:27 AM, DE VITO Dominique
wrote:
> > De : aaron morton [mailto:aa...@thelas
Hi,
Is compression working for whatever column value type ? in all cases ?
For example, if my CF has columns with value type of byte[] (or "blob" when
speaking CQL), is C* still doing compression ?
Thanks.
Regards,
Dominique
Hi Erwin,
Few books are coming out these months :
* Octobre : "Mastering Apache Cassandra"
http://www.packtpub.com/mastering-apache-cassandra/book
* November : " Cassandra High Performance Cookbook: Second Edition"
http://www.packtpub.com/cassandra-high-performance-cookbook/book
* December :
I don’t know : most of these books are not out, yet ;-)
[@@ THALES GROUP INTERNAL @@]
De : erwin.karb...@gmail.com [mailto:erwin.karb...@gmail.com] De la part de
Erwin Karbasi
Envoyé : lundi 28 octobre 2013 12:24
À : DE VITO Dominique
Cc : user@cassandra.apache.org
Objet : Re: Cassandra book
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