HADOOP

HADOOP

Create a data node

• install data node software

cd /triumfcs/trshare/olchansk/linux/hadoop/
rpm --import RPM-GPG-KEY-cloudera 
rpm -vh --install cdh3-repository-1.0-1.noarch.rpm-SL5 (or -SL6)
(cd $HOME; sh /triumfcs/trshare/olchansk/linux/hadoop/jdk-6u30-linux-x64-rpm.bin)
cd ~
yum install hadoop"*"datanode hadoop"*"fuse hadoop"*"native
chkconfig hadoop-0.20-datanode off

• FIXME: adjust hadoop UID/GID somehow - it is different on every machine! wrong, wrong, wrong!

• configure data node

ln -s /home/olchansk/sysadm/hadoop/conf.daq_test /etc/hadoop-0.20
alternatives --install /etc/hadoop-0.20/conf hadoop-0.20-conf /etc/hadoop-0.20/conf.daq_test 50
alternatives --display hadoop-0.20-conf
mkdir /data8/hdfs_data
chown -R hdfs.hdfs /data8/hdfs_data

• add /data8/hdfs_data to /home/olchansk/sysadm/hadoop/conf.daq_test/hdfs-site.xml:
  • add directory to dfs.data.dir
  • increase dfs.datanode.failed.volumes.tolerated by one (should be "number of dfs.data.dir entries" minus 1).

• start the data node: service hadoop-0.20-datanode start
• look at the log file: tail -100 /usr/lib/hadoop-0.20/logs/hadoop-hadoop-datanode-ladd08.triumf.ca.log

• mount hdfs: unset LD_LIBRARY_PATH; hadoop-fuse-dfs dfs://ladd12:8020 /mnt/xxx
• watch name node: http://ladd12.triumf.ca:50070
• watch data node: http://ladd08.triumf.ca:50075

Performance

• cluster with 3 data nodes: ladd12 (quad-core i7-860), ladd08 (dual opteron 2GHz), ladd05 (dual-core Athlon 2.6 GHz)
• hdfs mounted on ladd12
• write benchmark:

ladd12:olchansk$ /usr/bin/time dd if=/dev/zero of=xxx bs=1024k count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 31.3406 s, 33.5 MB/s
0.00user 0.18system 0:31.43elapsed 0%CPU (0avgtext+0avgdata 7104maxresident)k
0inputs+0outputs (0major+483minor)pagefaults 0swaps
ladd12:olchansk$ /usr/bin/time dd if=/dev/zero of=xxx2 bs=1024k count=10000
10000+0 records in
10000+0 records out
10485760000 bytes (10 GB) copied, 436.875 s, 24.0 MB/s
0.00user 1.72system 7:16.97elapsed 0%CPU (0avgtext+0avgdata 7104maxresident)k
0inputs+0outputs (0major+483minor)pagefaults 0swaps

ganglia reports peak network use 30 Mbytes/sec, ladd12: load 1, cpu use 10%, disk use 15%+15%busy; ladd05: load 2, cpu use 30%sys, 30%wait, disk use 15%+20%busy; ladd08: load 6, cpu use 30%sys, 70%wait, disk use 40%+40%busy.

• read benchmark:

ladd12:olchansk$ ls -l
total 11391305
-rw-r--r-- 1 olchansk nobody   130360111 Dec 28 18:36 run21600sub00000.mid.gz
-rw-r--r-- 1 olchansk nobody  1048576000 Jan  2 10:35 xxx
-rw-r--r-- 1 olchansk nobody 10485760000 Jan  2 10:37 xxx2
ladd12:olchansk$ /usr/bin/time dd if=run21600sub00000.mid.gz of=/dev/null
254609+1 records in
254609+1 records out
130360111 bytes (130 MB) copied, 1.55497 s, 83.8 MB/s
0.02user 0.08system 0:01.69elapsed 6%CPU (0avgtext+0avgdata 3024maxresident)k
254632inputs+0outputs (1major+227minor)pagefaults 0swaps
ladd12:olchansk$ 
ladd12:olchansk$ /usr/bin/time dd if=xxx of=/dev/null
2048000+0 records in
2048000+0 records out
1048576000 bytes (1.0 GB) copied, 11.4278 s, 91.8 MB/s
0.18user 0.69system 0:11.43elapsed 7%CPU (0avgtext+0avgdata 3008maxresident)k
2048000inputs+0outputs (0major+227minor)pagefaults 0swaps
ladd12:olchansk$ 
ladd12:olchansk$ /usr/bin/time dd if=xxx2 of=/dev/null
20480000+0 records in
20480000+0 records out
10485760000 bytes (10 GB) copied, 130.188 s, 80.5 MB/s
1.68user 7.10system 2:10.19elapsed 6%CPU (0avgtext+0avgdata 3024maxresident)k
20480000inputs+0outputs (0major+228minor)pagefaults 0swaps

no network use, cpu use ladd12 is 10%+30%wait, disk use is 0% because all data was cached in memory: 10GB file, 16GB RAM.