On 11/16/2011 04:06 PM, Thomas Oatess wrote: > Can someone please explain an ephemeral mount to me? How is it used?
Short answer for folks new to EC2: Run EBS boot instances and avoid using ephemeral storage like /mnt This advice will help you avoid a number of common and serious problems that can occur when using instance-store AMIs and ephemeral storage. Longer answer: Once you're using EC2 comfortably and want to start exploring more advanced topics, you can learn about ephemeral storage and think about if there might be use cases where you could gain a slight advantage in cost by using it. Ephemeral storage (including the root disk of instance-store instances) is free but the contents are completely lost forever whenever an instance is stopped, terminated, or fails. There is no way to recover. EBS storage (including the root disk of EBS boot instances) has a minor cost for the storage and for IO transactions, but is persistent through an instance being stopped or failing. By default, the root disk of an EBS boot instance is deleted when the instance is terminated, but you can modify the instance attributes to change this. Here's an article that talks about how to do it: Protect EC2 Instances from Accidental Termination and Loss of Data http://alestic.com/2010/01/ec2-instance-locking There are a number of other important reasons to use EBS boot instances instead of instance-store, but when you're just getting started, it's simplest and safest just to stick with EBS boot. Even as an expert, I always run EBS boot. I sometimes use /mnt as a big /tmp but that's about it. Everything else goes on EBS. -- Eric Hammond -- Ubuntu-cloud mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-cloud
