Also, what are you meaning specifically by 'slow'? Which measurements are you looking at. What are your baseline constraints for your test system?
2010/6/1 史英杰 <shiyingjie1...@gmail.com>: > 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 >> >> > >
