cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Olivier Mallassi <omalla...@octo.com>
Subject Local read/write vs write request
Date Wed, 11 Jul 2012 13:59:16 GMT
Hi all

During our load tests, we observe that a couple of servers are much more
used than others (in terms of CPU). In front of the cassandra cluster we
have a IPVS (ipvsadm configured in rr)

in opscenter we have the following graph :
Write / read Request : almost evenly distributed ...
[image: Inline image 1]

Local Writes / Read Request : clearly not evenly distributed and as you can
imagine, the high loaded nodes (in CPU) are the ones with more TPS....
[image: Inline image 2]


Based on that, my best idea is that load tests we are doing use data that
is physically located on a couple of server (bad luck....).

We tried using different data (in our load tests), so different key but the
behavior seem identical (we will repeat the tests).

Do you have any ideas of what can be wrong?

thx a lot.

-- 
............................................................
Olivier Mallassi
OCTO Technology
............................................................
50, Avenue des Champs-Elysées
75008 Paris

Mobile: (33) 6 28 70 26 61
Tél: (33) 1 58 56 10 00
Fax: (33) 1 58 56 10 01

http://www.octo.com
Octo Talks! http://blog.octo.com

Mime
View raw message