<div dir="ltr">Hello, list.<div><br></div><div style>Yesterday I was pleased to see that Centos has released official images at the aws marketplace. Nice job.</div><div style><br></div><div style>Today I started playing with the Centos 6.3 image (<a href="https://aws.amazon.com/marketplace/pp/B00A6L6F9I">https://aws.amazon.com/marketplace/pp/B00A6L6F9I</a>, on which I plan to deploy a gluster cluster in production soon) and noticed a weird thing.</div>
<div style><br></div><div style>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).<br>
</div><div style><br></div><div style>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.</div>
<div style><br></div><div style>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...</div>
<div style><br></div><div style>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.</div>
<div style><br></div><div style>Is there a reasonable reason for the 4 offset which makes it unchangeable? <br></div><div style><br></div><div style>It's just a thought. I think it's worth considering it..</div><div style>
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