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Had some data on ephemeral storage of a ec2 medium instance. They are lost between server reboot. I had a ami created just before the reboot. Is it supposed to contain that data? I had created a new instance from that ami but can't find the data on new ephemeral drive.

ok. I got it. Create Image only creates ebs backed ami. Creating instance storage backed ami is different. It is described here creating an instance store ami

orchidit
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Ephemeral drives on EC2 are, by definition, ephemeral. This means that their data in not kept between reboots, and not saved as part of the AMI image.

You can read more on what you can an cannot do with these kinds of disks here.

Uri Agassi
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  • its that here( [link]http://stackoverflow.com/a/11566285/1555414 ) someone stated "You can create an AMI from your current machine state, which will contain everything in your ephemeral storage. Then, when you launch a new instance based on that AMI it will contain everything as it is now." – orchidit Mar 09 '14 at 12:52
  • ok. I got it. Create Image only creates ebs backed ami. Creating instance storage backed ami is different. It is described here [creating an instance store ami][1] [1]: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/creating-an-ami-instance-store.html – orchidit Mar 09 '14 at 14:14
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    Wait, no. The data on the ephemeral drives *does* persist across reboots. It does not persist across an instance stop/start (which moves the instance to a different physical host) and of course doesn't survive termination... but across ordinary reboots, it absolutely should persist. – Michael - sqlbot Mar 09 '14 at 15:51
  • can amazon be requested to retrieve the data? just asking :) – orchidit Mar 09 '14 at 17:58
  • @orchidit Ephemeral volumes automatically get formatted to make room for the next host on the hardware. Data recovery is not possible. – datasage Mar 10 '14 at 00:30
  • Michael is correct, and you might actually just need to remount the ephemeral drive(s) if all you did was reboot not stop/start. Depending on whether the mounting is done autmatically at boot or not. Check ls -l /dev/disk – dmohr Mar 12 '14 at 00:57