Replication location is determined by the row key, not the location of
the client that inserted it. (Otherwise, without knowing what DC a
row was inserted in, you couldn't look it up to read it!)
On Fri, Jun 17, 2011 at 12:20 AM, AJ a...@dude.podzone.net wrote:
On 6/16/2011 9:45 PM, aaron
I haven't done it yet, but when I researched how to make
geo-diverse/failover DCs, I figured I'd have to do something like RF=6,
strategy = {DC1=3, DC2=3}, and LOCAL_QUORUM for reads/writes. This gives
you an ack after 2 local nodes do the read/write, but the data eventually
gets distributed to
Thanks Jonathan. I assumed since each data center owned the full key
space that the first replica would be stored in the dc of the
coordinating node, the 2nd in another dc, and the 3rd+ back in the 1st
dc. But, are you saying that the first endpoint is selected regardless
of the location of
On 6/17/2011 7:26 AM, William Oberman wrote:
I haven't done it yet, but when I researched how to make
geo-diverse/failover DCs, I figured I'd have to do something like
RF=6, strategy = {DC1=3, DC2=3}, and LOCAL_QUORUM for reads/writes.
This gives you an ack after 2 local nodes do the
On Fri, Jun 17, 2011 at 12:07 PM, AJ a...@dude.podzone.net wrote:
Thanks Jonathan. I assumed since each data center owned the full key space
that the first replica would be stored in the dc of the coordinating node,
the 2nd in another dc, and the 3rd+ back in the 1st dc. But, are you saying
What I don't like about NTS is I would have to have more replicas than I
need. {DC1=2, DC2=2}, RF=4 would be the minimum. If I felt that 2 local
replicas was insufficient, I'd have to move up to RF=6 which seems like a
waste... I'm predicting data in the TB range so I'm trying to keep
+1 for this if it is possible...
On Fri, Jun 17, 2011 at 6:31 PM, Eric tamme eta...@gmail.com wrote:
What I don't like about NTS is I would have to have more replicas than I
need. {DC1=2, DC2=2}, RF=4 would be the minimum. If I felt that 2 local
replicas was insufficient, I'd have to move up
Run two Cassandra clusters...
-Original Message-
From: Eric tamme [mailto:eta...@gmail.com]
Sent: Friday, June 17, 2011 11:31 AM
To: user@cassandra.apache.org
Subject: Re: Docs: Token Selection
What I don't like about NTS is I would have to have more replicas than
I need. {DC1=2
+1 Yes, that is what I'm talking about Eric. Maybe I could write my
own strategy, I dunno. I'll have to understand more first.
On 6/17/2011 10:37 AM, Sasha Dolgy wrote:
+1 for this if it is possible...
On Fri, Jun 17, 2011 at 6:31 PM, Eric tammeeta...@gmail.com wrote:
What I don't like
Hi Jeremiah, can you give more details?
Thanks
On 6/17/2011 10:49 AM, Jeremiah Jordan wrote:
Run two Cassandra clusters...
-Original Message-
From: Eric tamme [mailto:eta...@gmail.com]
Sent: Friday, June 17, 2011 11:31 AM
To: user@cassandra.apache.org
Subject: Re: Docs: Token
]
Sent: Friday, June 17, 2011 1:02 PM
To: user@cassandra.apache.org
Subject: Re: Docs: Token Selection
Hi Jeremiah, can you give more details?
Thanks
On 6/17/2011 10:49 AM, Jeremiah Jordan wrote:
Run two Cassandra clusters...
-Original Message-
From: Eric tamme [mailto:eta...@gmail.com
Yes. But, the more I think about it, the more I see issues. Here is what I
envision (Issues marked with *):
Three or more dc's, each serving as fail-overs for the others with 1 maximum
unavailable dc supported at a time.
Each dc is a production dc serving users that I choose.
Each dc also
On 6/17/2011 12:33 PM, Eric tamme wrote:
As i said previously, trying to build make cassandra treat things
differently based on some kind of persistent locality set it maintains
in memory .. or whatever .. sounds like you will be absolutely
undermining the core principles of how cassandra
On 6/17/2011 12:32 PM, Jeremiah Jordan wrote:
Run two clusters, one which has {DC1:2, DC2:1} and one which is
{DC1:1,DC2:2}. You can't have both in the same cluster, otherwise it
isn't possible to tell where the data got written when you want to read
it. For a given key XYZ you must be
Replication factor is defined per keyspace if i'm not mistaken. Can't
remember if NTS is per keyspace or per cluster ... if it's per
keyspace, that would be a way around it ... without having to maintain
multiple clusters just have multiple keyspaces ...
On Fri, Jun 17, 2011 at 9:23 PM, AJ
On 6/17/2011 1:27 PM, Sasha Dolgy wrote:
Replication factor is defined per keyspace if i'm not mistaken. Can't
remember if NTS is per keyspace or per cluster ... if it's per
keyspace, that would be a way around it ... without having to maintain
multiple clusters just have multiple
See this thread for background
http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Replica-data-distributing-between-racks-td6324819.html
In a multi DC environment, if you calculate the initial tokens for the entire
cluster data will not be evenly distributed.
Cheers
AJ,
sorry I seemed to miss the original email on this thread. As Aaron
said, when computing tokens for multiple data centers, you should
compute them independently for each data center - as if it were its
own Cassandra cluster.
You can have overlapping token ranges between multiple data
LOL, I feel Eric's pain. This double-ring thing can throw you for a
loop since, like I said, there is only one place it is documented and it
is only *implied*, so one is not sure he is interpreting it correctly.
Even the source for NTS doesn't mention this.
Thanks for everyone's help on
Thanks Eric! I've finally got it! I feel like I've just been initiated
or something by discovering this secret. I kid!
But, I'm thinking about using OldNetworkTopStrat. Do you, or anyone
else, know if the same rules for token assignment applies to ONTS?
On 6/16/2011 7:21 AM, Eric tamme
So, with ec2 ... 3 regions (DC's), each one is +1 from another?
On Jun 16, 2011 3:40 PM, AJ a...@dude.podzone.net wrote:
Thanks Eric! I've finally got it! I feel like I've just been initiated
or something by discovering this secret. I kid!
But, I'm thinking about using OldNetworkTopStrat.
On Thu, Jun 16, 2011 at 11:11 AM, Sasha Dolgy sdo...@gmail.com wrote:
So, with ec2 ... 3 regions (DC's), each one is +1 from another?
I dont use ec2, so I am not familiar with the specifics of deployment
there. That said, if you have 3 data centers with equal nodes in each
(so that you
But, I'm thinking about using OldNetworkTopStrat.
NetworkTopologyStrategy is where it's at.
A
-
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com
On 17 Jun 2011, at 01:39, AJ wrote:
Thanks Eric! I've finally got it! I feel like I've just
On 6/16/2011 9:45 PM, aaron morton wrote:
But, I'm thinking about using OldNetworkTopStrat.
NetworkTopologyStrategy is where it's at.
Oh yeah? It didn't look like it would serve my requirements. I want 2
full production geo-diverse data centers with each serving as a failover
for the
The problem in the above approach is you have 2 nodes between 12 to 4 in DC1
but from 4 to 12 you just have 1 (Which will cause uneven distribution
of data the node)
It is easier to think of the DCs as ring and split equally and interleave
them together
DC1 Node 1 : token 0
DC1 Node 2 :
Correction
The problem in the above approach is you have 2 nodes between 12 to 4 in
DC1 but from 4 to 12 you just have 1
should be
The problem in the above approach is you have 1 node between 0-4 (25%) and
and one node covering the rest which is 4-16, 0-0 (75%)
Regards,
/VJ
On Wed, Jun
All you heard is right...
You are not overriding Cassandra's token assignment by saying here is your
token...
Logic is:
Calculate a token for the given key...
find the node in each region independently (If you use NTS and if you set
the strategy options which says you want to replicate to the
Vijay, thank you for your thoughtful reply. Will Cass complain if I
don't setup my tokens like in the examples?
On 6/15/2011 2:41 PM, Vijay wrote:
All you heard is right...
You are not overriding Cassandra's token assignment by saying here is
your token...
Logic is:
Calculate a token for
No it wont it will assume you are doing the right thing...
Regards,
/VJ
On Wed, Jun 15, 2011 at 2:34 PM, AJ a...@dude.podzone.net wrote:
Vijay, thank you for your thoughtful reply. Will Cass complain if I don't
setup my tokens like in the examples?
On 6/15/2011 2:41 PM, Vijay
Ok. I understand the reasoning you laid out. But, I think it should be
documented more thoroughly. I was trying to get an idea as to how
flexible Cass lets you be with the various combinations of strategies,
snitches, token ranges, etc..
It would be instructional to see what a graphical
+1 for more documentation (I guess contributions are always welcomed) I
will try to write it down sometime when we have a bit more time...
0.8 nodetool ring command adds the DC and RAC information
http://www.datastax.com/dev/blog/deploying-cassandra-across-multiple-data-centers
This http://wiki.apache.org/cassandra/Operations#Token_selection says:
With NetworkTopologyStrategy, you should calculate the tokens the nodes
in each DC independantly.
and gives the example:
DC1
node 1 = 0
node 2 = 85070591730234615865843651857942052864
DC2
node 3 = 1
node 4 =
Yes... Thats right... If you are trying to say the below...
DC1
Node1 Owns 50%
(Ranges 8..4 - 8..5 8..5 - 0)
Node2 Owns 50%
(Ranges 0 - 1 1 - 8..4)
DC2
Node1 Owns 50%
(Ranges 8..5 - 0 0 - 1)
Node2 Owns 50%
(Ranges 1 - 8..4 8..4 - 8..5)
Regards,
/VJ
On Tue, Jun 14, 2011 at 3:47
Yes, which means that the ranges overlap each other.
Is this just a convention, or is it technically required when using
NetworkTopologyStrategy? Would it be acceptable to split the ranges
into quarters by ignoring the data centers, such as:
DC1
node 1 = 0 Range: (12, 16], (0, 0]
node
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