See https://bugzilla.redhat.com/show_bug.cgi?id=729586 On Tue, Jan 15, 2013 at 1:10 PM, Luis Fernando Alen <luis.alen at izap.com.br>wrote: > Hello, list. > > Yesterday I was pleased to see that Centos has released official images at > the aws marketplace. Nice job. > > Today I started playing with the Centos 6.3 image ( > https://aws.amazon.com/marketplace/pp/B00A6L6F9I, on which I plan to > deploy a gluster cluster in production soon) and noticed a weird thing. > > EBS Volumes attached to sd<X> are translated to xvd<Y> at the OS level. > However, after a few research and IRC chat, I figured out that it's not > weird, it's actually a normal and expected behavior (thanks for your help, > z00dax). > > sdX is actually mapped to xvdX+4. There is a consistent offset of 4. > Suppose you attach an ebs volume to /dev/sdf. It'll be translated to xvdj > at the OS level. sdg to xvdk, sdh to xvdl and so on. > > Allright. After having figured the mystery out, it became easy to work on > automations that deal with ebs volumes and file systems, such as volumes > created, attached and mounted on the fly, snapshots that freeze file > systems and so on... > > However, I really do think to myself: Wouldn't it be cleaner if the image > use simple translation (sdX to xvdX)? If I'm not wrong, Rightscale uses > this on their Centos images and it's much simpler. There's no extra work > needed to deal with that 4 offset when you want to automate things. > > Is there a reasonable reason for the 4 offset which makes it unchangeable? > > It's just a thought. I think it's worth considering it.. > > Luis Alen > www.izap.com.br > Ligue com tarifa local de todo o Brasil 4020.3000 > > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt at centos.org > http://lists.centos.org/mailman/listinfo/centos-virt > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos-virt/attachments/20130115/9cdf455a/attachment-0006.html>