> rite throughput is remaining at around 460 pkts/sec or sometimes even falling > below that rate as against the expected rate of around 920 pkts/sec. Is it > some kind of limitation of Cassandra or am I doing something wrong??? There is nothing in cassandra that would make that happen. Double check your client.
> I also see an > increase in packet drops when I try to store the packets from both the hosts > into the same keyspace. The packets are getting collected properly followed > by intervals in which they are being dropped in both the systems, at the same > time. Could this be some kind of a buffer issue??? What do you mean by packet drops ? Do you mean dropped messages in cassandra ? > Also, can write throughput be increased by distributing the write requests > between the 2 Cassandra nodes instead of sending the requests to a single > node? Currently, I dont see any improvement even if I distribute the write > requests to different hosts. How can I improve the write performance overall? Normally we expect 3k to 4k non counter writes per core per node, if you are not seeing that it may be configuration or the client. Hope that helps. ----------------- Aaron Morton New Zealand @aaronmorton Co-Founder & Principal Consultant Apache Cassandra Consulting http://www.thelastpickle.com On 15/12/2013, at 7:51 pm, Krishna Chaitanya <bnsk1990r...@gmail.com> wrote: > Hello, > I am a newbie to the Cassandra world and have a few doubts which I > wanted to clarify. I am having a software switch that stores netflow packets > into a shared memory segment and a daemon that reads that memory segment and > stores them into a 2-node Cassandra cluster. Currently, I am storing the > packets from 2 hosts into 2 different keyspaces, hence only writes and no > reads. The write throughput is coming to around 460 pkts/sec in each of the > keyspaces. But, when I try to store the packets into the same keyspace, I > observe that the write throughput is remaining at around 460 pkts/sec or > sometimes even falling below that rate as against the expected rate of around > 920 pkts/sec. Is it some kind of limitation of Cassandra or am I doing > something wrong??? > I also see an > increase in packet drops when I try to store the packets from both the hosts > into the same keyspace. The packets are getting collected properly followed > by intervals in which they are being dropped in both the systems, at the same > time. Could this be some kind of a buffer issue??? > The write requests from both the systems are > sent to the same node which is also the seed node. I am mostly using the > default Cassandra configuration with replication_factor set to 1 and without > durable_writes. The systems are i5s with 4 gb RAM. The data model is: each > second is the row key with all the packets collected in that second as the > columns. Also, can write throughput be increased by distributing the write > requests between the 2 Cassandra nodes instead of sending the requests to a > single node? Currently, I dont see any improvement even if I distribute the > write requests to different hosts. How can I improve the write performance > overall? > > Thanks. > -- > Regards, > BNSK.
