准备：
环境：
两台虚拟机：ip:192.168.138.128/129;配置：2核4G；
版本：apache-cassandra-3.10
ycsb-cassandra-binding-0.13.0-SNAPSHOT
系统参数优化：
1 时钟同步-----非常重要，涉及到集群内数据同步问题
在crontab中加上：
*/1 * * * * /usr/sbin/ntpdate time.nist.gov
2 关闭cpu变频控制
for CPUFREQ in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governordo
[ -f $CPUFREQ ] || continue
echo -n performance > $CPUFREQdone
3 在/etc/sysctl.conf增加配置文件：
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.rmem_default = 16777216
net.core.wmem_default = 16777216
net.core.optmem_max = 40960
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216
vm.max_map_count = 1048575
vm.swappiness=0
4 关闭zone_reclaim_mode
$ echo 0 > /proc/sys/vm/zone_reclaim_mode
5 增加cassandra用户控制 ：/etc/security/limits.d/cassandra.conf
<cassandra_user> - memlock unlimited
<cassandra_user> - nofile 100000
<cassandra_user> - nproc 32768
<cassandra_user> - as unlimited
6 redhat下需要修改/etc/security/limits.d/90-nproc.conf:
cassandra_user - nproc 32768
确认参数是否优化可以看cassandra进程号相关文件：
$ cat /proc/pid/limits
关闭使用swap分区：
swapoff --all
安装配置
不再赘述，直接解压放到指定地点就好了。需要注意的是在cassandra.yaml中需要更改以下配置：
cluster_name: ‘mycluster‘
data_file_directories:
- /data/cassandra/data
commitlog_directory: /data/cassandra/commitlog
saved_caches_directory: /data/cassandra/saved_caches
- seeds: "127.0.0.1,192.168.138.128,192.168.138.129"
listen_address: 192.168.138.128
rpc_address: 192.168.138.128
安装配置ycsb:
从github中下载最新版本的ycsb进行编译：
mvn -pl com.yahoo.ycsb:cassandra-binding -am clean package
（注意：mvn要用3版本，同时需要在编译本机环境开启一个127.0.0.1的cassandra并执行以下脚本：
CREATE KEYSPACE ycsb WITH replication = {‘class‘: ‘SimpleStrategy‘, ‘replication_factor‘: ‘3‘} AND durable_writes = true;
CREATE TABLE ycsb.usertable (
y_id text PRIMARY KEY,
field0 text,
field1 text,
field2 text,
field3 text,
field4 text,
field5 text,
field6 text,
field7 text,
field8 text,
field9 text
) WITH bloom_filter_fp_chance = 0.01
AND caching = {‘keys‘: ‘ALL‘, ‘rows_per_partition‘: ‘NONE‘}
AND comment = ‘‘
AND compaction = {‘class‘: ‘org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy‘, ‘max_threshold‘: ‘32‘, ‘min_threshold‘: ‘4‘}
AND compression = {‘chunk_length_in_kb‘: ‘64‘, ‘class‘: ‘org.apache.cassandra.io.compress.LZ4Compressor‘}
AND crc_check_chance = 1.0
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 0
AND gc_grace_seconds = 864000
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.0
AND speculative_retry = ‘99PERCENTILE‘;
）
然后解压包：cp /root/YCSB-master/cassandra/target/ycsb-cassandra-binding-0.13.0-SNAPSHOT.tar.gz ~/
如果报相关日志错误则下载：slf4j-1.7.25.tar.gz将相关的Log4j包放置到对应的lib目录下。
配置cassandra.properties:
hosts = 192.168.138.128,192.168.138.129
port = 9042
cassandra.keyspace = usertable
cassandra.username = dd
cassandra.password = 111111
cassandra.readconsistencylevel = ANY
cassandra.writeconsistencylevel = ANY
cassandra.maxconnections = 100
cassandra.connecttimeoutmillis = 1000000000
cassandra.readtimeoutmillis = 1000000000
配置workload:
- #vim workloads/workloada
- workload=com.yahoo.ycsb.workloads.CoreWorkload
- readallfields=false
- readproportion=0.5
- updateproportion=0.5
- scanproportion=0
- insertproportion=0
- requestdistribution=zipfian
- fieldcount 表示每条数据中的字段数,默认为 10;
- fieldlength 表示每个字段的值的长度,默认为 100;
- readallfields 域用来标识是否读取所有的所有的字段,取值有 ture 或 false;
- readproportion,
- updateproportion,
- scanproportion,
- insertproportion 分别表示该 workload中读、更新、扫描和插入操作占总操作的百分比,这四个值的和为 1;
- requestdistribution 表示数据的分布情况,当前支持 uniform,zipfian 和 latest,默认为 uniform;
- maxscanlength 域主要为扫描操作定义,定义了最大扫描的记录数量,默认为 1000;
- scanlengthdistribution 域也是为扫描操作定义的,为每次扫描的长度定义相应的分布,默认是 uniform;
- insertorder 域主要分两种 ordered 和 hashed,默认为 hashed;
- operationcount 总共的 operation 数量;
- maxexecutiontime 为该 workload 定义了最长的执行时间,单位为 s。
- AverageLatency(平均潜伏期)平均潜伏期（average latency）：指当磁头移动到数据所在的磁道后，然后等待所要的数据块继续转动（半圈或多些、少些）到磁头下的时间，单位为毫秒（ms）。平均潜伏期是越小越好，潜伏期小代表硬盘的读取数据的等待时间短，这就等于具有更高的硬盘数据传输率。
创建用户结构：
CREATE KEYSPACE usertable WITH replication = {‘class‘: ‘SimpleStrategy‘, ‘replication_factor‘: ‘1‘} AND durable_writes = true;
- create table usertable (y_id varchar primary key,field0 varchar,field1 varchar,field2 varchar,field3 varchar,field4 varchar,field5 varchar,field6 varchar,field7 varchar,field8 varchar,field9 varchar);
执行命令./bin/ycsb load cassandra-cql -P workloads/workloada -P cassandra.properties -p columnfamily=usertable -s -threads 20 > ./writeread-log.log
结果如下：
Datacenter: datacenter1; Host: /192.168.138.128; Rack: rack1
[OVERALL], RunTime(ms), 4974.0
[OVERALL], Throughput(ops/sec), 201.04543626859672
[TOTAL_GCS_Copy], Count, 13.0
[TOTAL_GC_TIME_Copy], Time(ms), 51.0
[TOTAL_GC_TIME_%_Copy], Time(%), 1.0253317249698433
[TOTAL_GCS_MarkSweepCompact], Count, 0.0
[TOTAL_GC_TIME_MarkSweepCompact], Time(ms), 0.0
[TOTAL_GC_TIME_%_MarkSweepCompact], Time(%), 0.0
[TOTAL_GCs], Count, 13.0
[TOTAL_GC_TIME], Time(ms), 51.0
[TOTAL_GC_TIME_%], Time(%), 1.0253317249698433
[CLEANUP], Operations, 200.0
[CLEANUP], AverageLatency(us), 11310.105
[CLEANUP], MinLatency(us), 0.0
[CLEANUP], MaxLatency(us), 2263039.0
[CLEANUP], 95thPercentileLatency(us), 0.0
[CLEANUP], 99thPercentileLatency(us), 1.0
[INSERT], Operations, 1000.0
[INSERT], AverageLatency(us), 230845.253
[INSERT], MinLatency(us), 2180.0
[INSERT], MaxLatency(us), 807423.0
[INSERT], 95thPercentileLatency(us), 659455.0
[INSERT], 99thPercentileLatency(us), 699903.0
[INSERT], Return=OK, 1000
参考资料：http://docs.datastax.com/en/landing_page/doc/landing_page/recommendedSettings.html
http://docs.datastax.com/en/cassandra/3.0/cassandra/tools/toolsCStress.html
http://blog.csdn.net/qianlong4526888/article/details/53747617