I read a blog article somewhere that RAID10 on EC2 cuts down performance by half compared to RAID0.
But when you have critical database data on the volumes, how else do you prevent data loss in case a volume goes bad?
(I just had a case where one of the volumes in a RAID0 array stopped responding…)
I do have master/slave replication with log shipping but don't want to do a fail-over if RAID10 can help me avoid it.
Best Answer
My understanding is that raid1 doubles the writes,but can speed up the reads a lot.
How large is your database and how fast can you make backups of it?
I also thought RAID0 (striping only) made it MORE likely you could have a problem,i.e. one volume is lost and its good bye data.
One of the unexpected I/O oddities of Ec2 EBS volumes, is the first time you write to your EBS disk, it takes like 2x longer, than any subsequent write. I do a disk fillup to 50% with just dd if=/dev/zero of=/newdisk/bigfile1 bs=1024m count=1024, then wipe the big files and afterwards writes take more normal speeds.
This is a good ec2 dev forum article on ec2 disk I/O specifics. https://forums.aws.amazon.com/thread.jspa?messageID=220860
and this says EBS disks are bad for raid10
Amazon EC2 Disk Performance | AF-Design Feb 27, 2009 ... If you have a high number of reads or writes, which you likely do .... Pingback: Amazon EC2 Disk Performance and Why RAID 10 is bad for EBS ... http://af-design.com/blog/2009/02/.../amazon-ec2-disk-performance/