killasmurf86 said:
So what is so good about tape, that you still use it?
[I have never ever used/seen tape, I'm just a desktop user]
I don't seep problem keeping backups on HDD's, as long as you properly maintain them.
Btw what do you store on 1TB?
Pls understand that my/our strategies are "in transition" and may not make total sense now vs when they may have started 5-10 years ago, when things were different -- hence these questions in this thread...
I store many GBs of medical research imaging data, as well as the usual documents, papers, presentations, etc.
I don't believe I have ever totally lost a single file in 30 years. And the times I have lost the most recent copy of a file I can count on one hand.
So tape... it USED to be that tape was 10-1000X cheaper than disk on a per byte basis. Its not that I particularly care for tape over disk backup. But I care about PROPER backups. Here is a casual list of some of the requirements for backup:
- ability to restore the state of a filesystem (or single file) across the whole lifetime of that filesystem (or file), sampled (snapshot) at certain intervals. I used to keep "monthly"'s FOREVER. I think keeping at least yearlies forever would be a minimum, with exponential-like frequency for more recent snapshots. For example, every year, plus every month for the past 2 years, plus every week for the past 2 months...
- ability to restore the system from scratch with only modest effort (not reading in 100 tapes/floppies/whatever).
- ability to read backups at least for 20 years.
- offsite/multisite storage, so that a fire/theft of a single site doesn't wipe you out.
then some niceties: minimal operator intervention, minimal time required, minimal down time of system, online backups possible, etc.
What's wrong with disk? maybe nothing... it depends on what you mean by "disk backup"... does it meet all the criterion listed above?
What's wrong with simply copying one disk to another?
- you only get one copy (or N copies, where N is very small), which means only N snapshots in time.
- there is appreciable chance that you will not be able to read current disks 10-15 years from now,
- not that easy to store at a separate site (stacks of hard drives on a shelf in another building?),
- and somewhat fragile to transport around...
My main points are:
- when one buys a 1TB disk for $100, that isn't the same as 1TB of PROPERLY backed up storage, which may cost more like $1000...
- people don't have a real appreciation for proper backups -- it used to be at any well-run data center, if you lost a file from a few days ago, they would be able to restore it for you without any question or issue...
- now that tape is no longer so cheap, relatively, there seems to be few, well-thought-out tools, strategies and software for affordable but solid backups...
Unix dump/restore was great... but what tools exist now to address the changing landscape in media (disk cheaper than tape), while retaining the same priorities and requirements of true backups?