Yeah it's very unlikely that you will have 2 nodes in the cluster with NO
intersecting token ranges (vnodes) for an RF of 3 (probably even 2).
If node A goes down all 256 ranges will go down, and considering there are
only 49 other nodes all with 256 vnodes each, it's very likely that every
node w
Thanks Alexander!
I'm not a MS in math too) Unfortunately.
Not sure, but it seems to me that probability of 2/49 in your explanation
doesn't take into account that vnodes endpoints are almost evenly distributed
across all nodes (al least it's what I can see from "nodetool ring" output).
htt
>
> As you said, the auto_bootstrap setting was turned on.
Well I was talking about the 'auto_snapshot' ;-). I understand that's what
you meant to say.
This command seems to apply only to one node. Can it be applied
> cluster-wide? Or should I run this command on each node?
Indeed, 'nodetool c
I was corrected off list that the odds of losing data when 2 nodes are down
isn't dependent on the number of vnodes, but only on the number of nodes.
The more vnodes, the smaller the chunks of data you may lose, and vice
versa.
I officially suck at statistics, as expected :)
Le lun. 15 janv. 2018
Hi Kyrylo,
the situation is a bit more nuanced than shown by the Datastax diagram,
which is fairly theoretical.
If you're using SimpleStrategy, there is no rack awareness. Since vnode
distribution is purely random, and the replica for a vnode will be placed
on the node that owns the next vnode in
Thanks, Rahul.
But in your example, at the same time loss of Node3 and Node6 leads to loss of
ranges N, C, J at consistency level QUORUM.
As far as I understand in case vnodes > N_nodes_in_cluster and
endpoint_snitch=SimpleSnitch, since:
1) "secondary" replicas are placed on two nodes 'next'
Not necessarily. It depends on how the token ranges for the vNodes are
assigned to them. For example take a look at this diagram
http://docs.datastax.com/en/archived/cassandra/2.0/cassandra/architecture/architectureDataDistributeDistribute_c.html
In the vNode part of the diagram, you will see that
Hi,
Let's say we have a C* cluster with following parameters:
- 50 nodes in the cluster
- RF=3
- vnodes=256 per node
- CL for some queries = QUORUM
- endpoint_snitch = SimpleSnitch
Is it correct that 2 any nodes down will cause unavailability of a keyrange at
CL=QUORUM?
Regards,
K
Hi,
It might really be a long shot, but I thought UserDefinedCompaction
triggered by JMX on a single sstable might remove data the node does not
own (to answer your " *Any other way to re-write SSTables with data a node
owns after a cluster scale out" *question part)
I might be wrong though
On
