Hi, I tried,
1-consistency level ZERO 2-JVM heap 4GB 3-normal Memtable cache and now I have about 30% improvment. However I want to know if you have also done w/r benchmark and what's the result? ?? 2010-06-02???? 11:35 +0800??lwl?????? > and, why did you set "JVM has 8G heap"? > 8g, seems too big. > > ?? 2010??6??2?? ????11:20??lwl <lwl.ro...@gmail.com>?????? > 3.32 concurrent read & 128 write in storage-conf.xml, other > cache > enlarged as well. > -------------------- > > > maybe you can try to decrease the size of caches. > > ?? 2010??6??2?? ????11:14??Shuai Yuan > <yuansh...@supertool.net.cn>?????? > > > ?? 2010-06-02???? 10:37 +0800??lwl?????? > > is all the 4 servers' MEM almost 100%? > > > Yes > > > > ?? 2010??6??2?? ????10:12??Shuai Yuan > <yuansh...@supertool.net.cn>?? > > ???? > > Thanks lwl. > > > > Then is there anyway of tuning this, faster > flush to disk or > > else? > > > > Cheers, > > > > Kevin > > > > ?? 2010-06-02???? 09:57 +0800??lwl?????? > > > > > MEM: almost 100% (16GB) > > > ----------------- > > > maybe this is the bottleneck. > > > writing concerns Memtable and SSTable in > memory. > > > > > > ?? 2010??6??2?? ????9:48??Shuai Yuan > > <yuansh...@supertool.net.cn>?? > > > ???? > > > ?? 2010-06-01???? 15:00 -0500?? > Jonathan Shook?????? > > > > Also, what are you meaning > specifically by 'slow'? > > Which > > > measurements > > > > are you looking at. What are > your baseline > > constraints for > > > your test > > > > system? > > > > > > > > > > Actually, the problem is the > utilizaton of > > resources(for a > > > single > > > machine): > > > CPU: 700% / 1600% (16 cores) > > > MEM: almost 100% (16GB) > > > Swap: almost 0% > > > Disk IO(write): 20~30MB / 200MB > (7.2k raid5, > > benchmarked > > > previously) > > > NET: up to 100Mbps / 950Mbps > (1Gbps, tuned and > > benchmarked > > > previously) > > > > > > So the speed of generating load, > about 15M/s as > > reported > > > before seems > > > quite slow to me. I assume the > system should get at > > least > > > about 50MB/s > > > of Disk IO speed. > > > > > > MEM? I don't think it plays a > major role in this > > writing game. > > > What's > > > the bottleneck of the system? > > > > > > P.S > > > about Consistency Level, I've > tried ONE/DCQUORUM and > > found ONE > > > is about > > > 10-15% faster. However that's > neither a promising > > result. > > > > > > Thanks! > > > > > > Kevin > > > > > > > > > > > 2010/6/1 ?????? > <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? > > > > > > > > > > ?? 2010??6??1?? ????4:48?? > Shuai Yuan > > > <yuansh...@supertool.net.cn>?????? > > > > >> > > > > >> 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 > > > > >> > > > > >> > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > Kevin Yuan > > > www.yuan-shuai.info > > > > > > > > > > > > > > > > > > > > > -- > > Shuai Yuan ???? > > Supertool Corp. ?????????????????????????? > > > > www.yuan-shuai.info > > > > > > > > > -- > > Shuai Yuan ???? > Supertool Corp. ?????????????????????????? > www.yuan-shuai.info > > > > > > > -- Shuai Yuan ???? Supertool Corp. ?????????????????????????? www.yuan-shuai.info
