Hi, It would be better if we know which Consistency Level did you choose, and what is the schema of test data?
在 2010年6月1日 下午4:48，Shuai Yuan <yuansh...@supertool.net.cn>写道： > Hi all, > > I'm testing writing speed of cassandra with 4 servers. I'm confused by > the behavior of cassandra. > > ---env--- > load-data app written in c++, using libcassandra (w/ modified batch > insert) > 20 writing threads in 2 processes running on 2 servers > > ---optimization--- > 1.turn log level to INFO > 2.JVM has 8G heap > 3.32 concurrent read & 128 write in storage-conf.xml, other cache > enlarged as well. > > ---result--- > 1-monitoring by `date;nodetool -h host ring` > I add all load together and measure the writing speed by > (load_difference / time_difference), and I get about 15MB/s for the > whole cluster. > > 2-monitoring by `iostat -m 10` > I can watch the disk_io from the system level and have about 10MB/s - > 65MB/s for a single machine. Very big variance over time. > > 3-monitoring by `iptraf -g` > In this way I watch the communication between servers and get about > 10MB/s for a single machine. > > ---opinion--- > So, have you checked the writing speed of cassandra? I feel it's quite > slow currently. > > Could anyone confirm this is the normal writing speed of cassandra, or > please provide someway of improving it? > -- > Kevin Yuan > www.yuan-shuai.info > > >
