On 04/20/2011 03:43 PM, Mohit Anchlia wrote: > Thanks! Is there any recommended configuration you want me to use when > using mdadm? > > I got this link: > > http://tldp.org/HOWTO/Software-RAID-HOWTO-5.html#ss5.1 First things first, break the RAID0, and then lets measure performance per disk, to make sure nothing else bad is going on. dd if=/dev/zero of=/dev/DISK bs=128k count=80k oflag=direct dd of=/dev/null if=/dev/DISK bs=128k count=80k iflag=direct for /dev/DISK being one of the drives in your existing RAID0. Once we know the raw performance, I'd suggest something like this mdadm --create /dev/md0 --metadata=1.2 --chunk=512 \ --raid-devices=4 /dev/DISK1 /dev/DISK2 \ /dev/DISK3 /dev/DISK4 mdadm --examine --scan | grep "md\/0" >> /etc/mdadm.conf then dd if=/dev/zero of=/dev/md0 bs=128k count=80k oflag=direct dd of=/dev/null if=/dev/md0 bs=128k count=80k iflag=direct and lets see how it behaves. If these are good, then mkfs.xfs -l version=2 -d su=512k,sw=4,agcount=32 /dev/md0 (yeah, I know, gluster folk have a preference for ext* ... we generally don't recommend ext* for anything other than OS drives ... you might need to install xfsprogs and the xfs kernel module ... which kernel are you using BTW?) then mount -o logbufs=4,logbsize=64k /dev/md0 /data mkdir stress dd if=/dev/zero of=/data/big.file bs=128k count=80k oflag=direct dd of=/dev/null if=/data/big.file bs=128k count=80k iflag=direct and see how it handles things. When btrfs finally stabilizes enough to be used, it should be a reasonable replacement for xfs, but this is likely to be a few years. -- Joseph Landman, Ph.D Founder and CEO Scalable Informatics Inc. email: landman at scalableinformatics.com web : http://scalableinformatics.com http://scalableinformatics.com/sicluster phone: +1 734 786 8423 x121 fax : +1 866 888 3112 cell : +1 734 612 4615
