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Questions tagged [cassandra]

Apache Cassandra is an open source distributed key-value database cluster, designed to scale linearly when adding nodes. It provides multi-datacenter replication.

It was designed to handle very large amounts of data spread out across many commodity servers while providing a highly available service with no single point of failure. It is a NoSQL solution that was initially developed by Facebook and powered their Inbox Search feature until late 2010.

Official page

Source: wikipedia

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Incredibly high load average on a Centos server

I have a Centos 6.4 server that's being used as a Cassandra node in a production environment, it is still working and responding to queries etc, but the load average is rather "high" a.k.a. buggy? In any case, you have to see it for yourself: Has…
Sergio Ayestarán
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cassandra nodetool repair - how to schedule properly?

Im putting together a 16 node cassandra cluster (replication factor 2) and want to setup a schedule for nodetool repair. gc_grace_seconds is at the default. Two questions: My first impulse is to setup a cron job for each machine and attempt to…
ethrbunny
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Operator \> and \< (string version comparison) are not recognised in shell script

I am trying to run Casandra nodetool and getting warnings coming from .sh script. [root@d11ca4cc-fa95-c8a9-e133-e64c434f0e6f ~]# nodetool status /opt/local/share/cassandra/bin/nodetool[53]: .[97]: [: <: unknown…
ruruskyi
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How to authenticate with cassandra-stress 2.1

Is there a way to authenticate to cassandra using the new cassandra-stress tool released with cassandra 2.1? It appears as if the '-un' (username) and '-pw' (password) switches have been removed from the tool. In the 2.0 version, this is the…
jd1
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Cassandra 2.x - cluster does not rebalance after adding new nodes

I had 3 nodes, all with ~550GB, and added 4 more. I hoped that data would migrate on its own from old servers to new ones. Unfortunately after one day, data seems to stay in old places. In parallel, there is a constant stream of incoming data, and…
Jacek Kaniuk
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Can I run multiple nodes of Cassandra on my mac without a virtual machine for each?

You can see in the doco here that setting up each instance of Cassandra requires a new 'node'. My question is - to run a cluster with multiple nodes of Cassandra on my Mac (Running Mavericks) - do I need to spin up a virtual machine for each - or…
Hawkeye
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How can I view the cache-hit ratio for a single column-family in Cassandra?

I've enabled row-caching in for one of my column-families in Cassandra and I'l like to view the cache-hit ratio? I can see the cache-hit ration metric in Cassandra's OspCenter but it seems to show me the information for the entire cluster? Is there…
Mridang Agarwalla
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DataStax OpsCenter 3.2.2 fails to start properly when storing collection data on different server

I'm trying to run OpsCenter 3.2.2 (enterprise edition) using a separate cluster used for storing the collection data. I specify the [storage_cassandra] tag in the cluster configuration. When starting opscenter, the log shows the…
Jimmy Mårdell
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Cannot generate cluster reports in OpsCenter.

I cannot generate a cluster report in OpsCenter. The server and clients are running on CentOS 5.9, 64bit. Software versions: opscenter-3.2.2-1 opscenter-agent-3.2.2-1 Here is the error reported in the web browser: There was an error generating…
Gene
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I'm moving nodes around on a Cassandra cluster, and seeing "Back pressure disabled!" in the logs

I'm moving nodes around on a Cassandra cluster, and seeing Back pressure disabled! in the log. I'm also seeing (around a minute earlier) Back pressure enabled with average index queue size: 1106. What do these mean? Are they bad? Thanks!
Curtis
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Diskless Cassandra nodes?

Would it be at all feasible to use diskless nodes for cassandra? Im imagining a setup with one 'master node' that had all the appropriate software, disks, etc and the rest would PXE boot. The setup would do its compaction and write-back to a SAN (or…
ethrbunny
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Dynamically changing one-node Cassandra cluster to two nodes

So I have an application that will be very dormant most of the time but will need high-bursting a few days out of the month. Since we are deploying on EC2 I would like to keep only one Cassandra server up most of the time and then on burst days I…
Jason Axelson
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Reconfiguring data directories in an existing Cassandra node

I'm currently running a very simple single-node Cassandra box with the data files on a single disk. I'm about to add a couple of SSDs to the box and intend to add each SSD as another data directory to the cassandra.yaml file. If I stop Cassandra,…
Nathan Ridley
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How do I automatically add Cassandra nodes to Windows DNS?

I'm working on building a new Cassandra cluster and I'd like to create a DNS record that will hold the IP addresses of all of the nodes. I build all of my servers in the cloud and they automatically create a new A record for themselves when they…
GregB
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Many concurrent Cassandra database connections thru SSH tunnel

I have an application that uses the PyCassa Cassandra client to open many concurrent connections to a Cassandra server. When I run the client application locally on the database server, it works. However, when i forward the Cassandra port thru an…
bshanks
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