Hello,
My company is using Duply to back up data in the following manner to S3:
Monday-Saturday: incremental backup
Sunday: full backup
Each time a full backup is made, a signature file is created and placed in the server's local cache as well as the S3 bucket.
Our S3 bucket policy is to hold backups in standard storage for 9 days, then move the backups to Glacier. After roughly 2 years, the data is deleted from Glacier.
With this in mind, I have the following questions:
1. Let's say I lose the signature file from the first week of September of last year. Can I still restore backups from the previous to and following that week, provided I have all the other signature files?
2. We never expire (purge?) our backups, so based on our S3 aging policy, we will start erasing backups in two years, including signature files. Can we still restore backups even with these older files being gone? For instance, can I restore a backup from two weeks ago if the signature files from two years ago have been deleted?
3. Something bad happens to a server and we lose the original .cache files stored locally on that server. We have the backup files and signature file for the last week in standard storage in a S3 bucket, with the rest of the files for older backups residing in Glacier. Can I restore from a backup from yesterday with what's already in standard storage, or do I need to restore all previous backups to standard storage first?
4. Does a full backup contain only the state of files at the time the full backup was made, or are the all the changes to those files since the last full also contained in the full? For instance, I have a file named spam.txt that contains the word "spam" on Tuesday and on Wednesday I add the line "and eggs" to it. Does the full backup of that file contain both versions, or only the "spam and eggs" version?
5. Do I need to keep al the incremental backups of all previous backups to be able to successfully restore from the most recent backup if we're not using purge?
Sorry, lots of questions, but Google isn't being my friend on the answers.
Thank you for your time,
-- Mike Beebe
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