Are you using the Ubuntu operating system ? Cheers
----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 18/05/2012, at 1:59 PM, koji Lin wrote: > Hi > > We use amazon ami 3.2.12-3.2.4.amzn1.x86_64 > > and some of our data file are more than 10G > > thanks > > koji > > 2012-5-16 下午6:00 於 "aaron morton" <aa...@thelastpickle.com> 寫道： > On Ubuntu ? Sounds like http://wiki.apache.org/cassandra/FAQ#ubuntu_hangs > > Cheers > > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 16/05/2012, at 2:13 PM, koji Lin wrote: > >> Hi >> >> Our service already run cassandra 1.0 on 1x ec2 instances(with ebs), and we >> saw lots of discussion talk about using ephemeral raid for better >> performance and consistent performance. >> >> So we want to create new instance using 4 ephemeral raid0, and copy the data >> from ebs to finally replace the old instance and reduce some . >> >> we create the xlarge instance with -b '/dev/sdb=ephemeral0' -b >> '/dev/sdc=ephemeral1' -b '/dev/sdd=ephemeral2' -b '/dev/sde=ephemeral3', >> >> and use mdadm command like this mdadm --create /dev/md0 --level=0 -c256 >> --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde >> >> after copying file and start the cassandra(same token as old instance it >> replaced). >> >> we saw the read is really fast always keep 2xxm/sec, but system load exceed >> 40, with high iowait, and lots of client get timeout result. We guess maybe >> it's the problem of ec2 instance, so we create another one with same setting >> to replace other machine ,but the result is same . Then we rollback to ebs >> with single disk ,read speed keeps at 1xmb/sec but system becomes well >> .(using ebs with 2 disks raid0 will keep at 2xmb/sec and higher iowait then >> single disk ,but still works) >> >> Is there anyone meet the same problem too ? or do we forget something to >> configure? >> >> thank you >> >> koji >> >
