Amazon Glacier is an amazing way to store data you no longer need, but want to keep just in case you might some day.
Amazon promotes Glacier as an archival service, although some have been using it to backup their data.
But should you?
It’s important to distinguish between a backup and an archive.
A backup is redundant storage of your data, easily retrievable in the event of a disaster, such as a fire, corruption, or accidental deletion of your files.
An archive is the storage of data you will never need in the immediate future, but need to keep around, such as tax records.
When backing up your system, you will most certainly want to keep data for a certain period of time, or up to a certain total backup size. Doing so means pruning and overwriting old data that’s up on Glacier. Due to the way Glacier is designed, this is not easily done. You can not update old data nor overwrite it. Each time you update and upload a file on your system, another fresh copy is stored.
As of when this article was written, most backup apps with Glacier capability will happily backup your data to Glacier, but won’t prune your old data. I suppose it is possible, but the backup apps would have to be smart about how it places files into archives and vaults. Until that happens, you will be keeping old backups and revisions of files forever, and although not that expensive, paying for it too.
Keep mind that anything uploaded to Glacier is not meant to be easily retrievable. It will take up to 4 hours for your data to be made available for download. When disaster strikes and you want your data, you want it now, not in 4 hours time.
So there you have it.
Do I think Glacier makes a good backup solution?
Does it make a good archival solution?
Note: This is an opinion piece and reflects mine only. I use a Mac with Arq and previously backed up to Glacier. After discovering all the downsides to backing up to Glacier, I now backup to S3 instead.