After stop of the instance, which uses ephermeral data store, I will loose all data. Is it correct ?
To be specific, after you terminate or stop a node, any data on instance-specific storage will be lost. A reboot is different, and your data is intact in those cases. I am using these terms to match the terms in the AWS console.
To confuse matters slightly, some EBS-backed nodes also have some instance-specific storage. All instance-storage nodes are 100% instance-backed, though. So you really need to understand whether your data is hitting an EBS disk or instance-local storage.
I noticed that EBS store has been created automatically for my instance. I have created few files in home directory, but this files were not deleted after reboot. So where is ephermeral data is stored ?
Several points here:
- For an EBS-backed instance, your /home partition is on the EBS root device, and hence data will persist provided the volume exists.
- Again a reboot wouldn't delete your data even if you had an instance-storage node, but it sounds like you chose an EBS-backed node.
- If you had instead created these files in
/mnt, then stopped your instance and later started it again, you might have lost them. Again it depends exactly which ec2 node type you're running.
Regarding your last point - I would recommend that you just make sure your data is being stored on some EBS backed disk. Whether that is your root device or a separate EBS volume is up to you and depends on your specific needs.
