Just a small warning: I've seen kernel panics with the XFS kernel module once you have many disks (in my case: > 20 disks). This is an exotic amount of disks to put in one server so it shouldn't hold anyone back from using XFS :-)
2011/5/7 Rita <rmorgan...@gmail.com> > Sheng, > > How big is your each XFS volume? We noticed if its over 4TB hdfs won't pick > it up. > > > 2011/5/6 Ferdy Galema <ferdy.gal...@kalooga.com> > >> No unfortunately not, we couldn't because of our kernel versions. >> >> >> On 05/06/2011 04:00 AM, ShengChang Gu wrote: >> >> Many thanks. >> >> We use xfs all the time.Have you try the ext4 filesystem? >> >> 2011/5/6 Ferdy Galema <ferdy.gal...@kalooga.com> >> >>> Hi, >>> >>> We've performed tests for ext3 and xfs filesystems using different >>> settings. The results might be useful for anyone else. >>> >>> The datanode cluster consists of 15 slave nodes, each equipped with 1Gbit >>> ethernet, X3220@2.40GHz quadcores and 4x1TB disks. The disk read speeds >>> vary from about 90 to 130MB/s. (Tested using hdparm -t). >>> >>> Hadoop: Cloudera CDH3u0 (4 concurrent mappers / node) >>> OS: Linux version 2.6.18-238.5.1.el5 (mockbu...@builder10.centos.org) >>> (gcc version 4.1.2 20080704 (Red Hat 4.1.2-50)) >>> >>> #our command >>> for i in `seq 1 10`; do ./hadoop jar ../hadoop-examples-0.20.2-cdh3u0.jar >>> randomwriter -Ddfs.replication=1 /rand$i && ./hadoop fs -rmr /rand$i/_logs >>> /rand$i/_SUCCESS && ./hadoop distcp -Ddfs.replication=1 /rand$i >>> /rand-copy$i; done >>> >>> Our benchmark consists of a standard random-writer job followed by a >>> distcp of the same data, both using a replication of 1. This is to make sure >>> only the disks get hit. Each benchmark is ran several times for every >>> configuration. Because of the occasional hickup, I will list both the >>> average and the fastest times for each configuration. I read the execution >>> times off the jobtracker. >>> >>> The configurations (with exection times in seconds of Avg-writer / >>> Min-writer / Avg-distcp / Min-distcp) >>> ext3-default 158 / 136 / 411 / 343 >>> ext3-tuned 159 / 132 / 330 / 297 >>> ra1024 ext3-tuned 159 / 132 / 292 / 264 >>> ra1024 xfs-tuned 128 / 122 / 220 / 202 >>> >>> To explain, ext3-tuned is with tuned mount options >>> [noatime,nodiratime,data=writeback,rw] and ra1024 means a read-ahead buffer >>> of 1024 blocks. The xfs disks are created using mkfs options >>> [size=128m,lazy-count=1] and mount options [noatime,nodiratime,logbufs=8]. >>> >>> In conclusion it seems that using tuned xfs filesystems combined with >>> increased read-ahead buffers increased our basic hdfs performance with about >>> 10% (random-writer) to 40% (distcp). >>> >>> Hopefully this is useful to anyone. Although I won't be performing more >>> tests soon I'd be happy to provide more details. >>> Ferdy. >>> >> >> >> >> -- >> 阿昌 >> >> > > > -- > --- Get your facts first, then you can distort them as you please.-- >
