Document that AWS backup doesn't always backup files written immediately before taking a backup

Question

I have noticed that AWS backup for EFS is not behaving as I was expecting.  There appear to be delays occasionally on the files backed up by AWS backup.

Example Scenario:
1.   Save fileA.txt to EFS
2.   Take a AWS backup immediately afterwards
3.   Restore the backup.

I find that fileA.txt doesn't exist in the restore but exists in the file system. It appears files saved immediately before taking a backup are not guaranteed to be backed up.

Is this the case? If so can this be documented in the AWS docs.
If not is this a bug?

Answer

Amazon EFS is designed to be highly available. You can access and modify your Amazon EFS file systems while your backup is occurring in AWS Backup. However, inconsistencies, such as duplicated, skewed, or excluded data, can occur if you make modifications to your file system while the backup is occurring. These modifications include write, rename, move, or delete operations. To ensure consistent backups, we recommend that you pause applications or processes that are modifying the file system for the duration of the backup process. Or, schedule your backups to occur during periods when the file system is not being modified.

https://docs.aws.amazon.com/efs/latest/ug/awsbackup.html#backup-consistency

Document that AWS backup doesn't always backup files written immediately before taking a backup

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