tape is cheap, portable, and fast transfer rate
Tape will be the meduim of choice for off siting data, once you have more than a few terrabytss of data network transfer becomes too long especially for restores.
Tape has pretty much been rescued over the past year by revelations that both Google and Amazon were using tape libraries for data archiving purposes.If these glamorous, bleeding edge online cloud service provider firms used boring old legacy tape then, hey, the stuff must still really be useful. It was a mixed picture though …
Not if you know anything about disk based backup it doesn't. You seem to be under the impression that disk based backup works even remotely like tape based backup. Restores on a proper system are immediate because you restore from the local recovery point. Only in disaster recovery would you need to use the remote copy, and then it is in fact the local copy.
When you start getting into large data sets its quicker to recall the tape offsite than to wait for the data to be replicated from offsite even with dedicated links and networks . Most large enterprises use disk to disk to tape . Tape is not sexy but it is very effective in many circumstances. If you need to offsite large amounts of data tape is still the most sensible option. Sneaker net is still very much alive and well. As someone who started his career in IT as a tape monkey swapping out DAT tapes at 3am in the morning and hoping I got the second tape in the drive before the job timed out , I have no rose tinted view of tape backups. However it does seem to fashionable to bash tape backups when they are still the best tool for the job in many circumstances.
"When you start getting into large data sets its quicker to recall the tape offsite than to wait for the data to be replicated from offsite even with dedicated links and networks . Most large enterprises use disk to disk to tape ."
Most large enterprises use tape out of tradition and fear rather than necessity. Also because many admins seem to believe that a backup tape is some kind of archive - it's not.
When you're working with large data sets it's actually quicker to recall from the online snapshot in a highly resilient and redundant SAN than it is to recall a tape even from the same room. Just because data and recovery points replicate off site does not mean they cease to be available in the primary site so no WAN access is necessary to recover data within the backup system.
Disaster recovery is a different matter altogether. If there is a disaster then you won't be operating from the same data centre anyway and so as I said the remote copy would be your new local copy. In this scenario, with SAN boot or virtualisation you just switch on the systems at the remote site and they already have their data. No need for "bare metal recovery" or streaming from tapes, you just switch on and smile at your boss.
All of this assumes you have a second data centre of course, but if you don't then online disk based backup is rather less useful and tape may be the better option.
Yep good admins are paranoid. Triumph over experience over optimisim. But tape is still cheaper than disk and more portable. SAN fails , databases get corrupted and you dont ever find out how good your BCP is till you have to use it. Tape isnt fasionable but it still has its place.
It depends what your disaster recovery scenarios are. If you are storing data offsite because you need business continuity through a disaster that takes out your online data and primary backup, then you have to have a firm plan for how to get the data back intact from offsite tape within your DR window, onto enough surviving hardware to continue operations. If you are mostly storing a copy offsite to guarantee the survival of the archive itself - say, if the primary copy is physically far enough from your online data that it could be lost in a disaster without losing the actual online copy and servers - then you just need to plan how you'll re-replicate the archive at acceptable risk.
My workplace (nci.org.au) is progressively deploying petabytes of online research data storage. At that scale, tape backup has big power/cost/durability advantages, and so that's our chosen medium. But as our primary tape system has to live in our main data centre with the online storage, almost any DR scenario that requires our offsite data copy will necessarily involve significant lead time to buy in more disk and other hardware to replace the failed/destroyed equipment; there is not the budget for continuous availability of this kind of data at this scale through disaster scenarios. Even so, we are working on strategies for minimizing the time to restore from tape, with particular regard to the very wide range of file sizes within our online datasets. Restoring tiny files from tape at media rates requires a lot of metadata IOPS, and we are taking into account the access patterns typical for each dataset before deciding how it should be packaged for long-term storage and backup.
I hadn't thought about DAT for a *long* time, but a quick check of the price for a 160GB native capacity "DAT-320" tape (even the product branding assumes all your data is 2:1 compressible) is somewhere around AUD$35, whereas a 1.5TB native capacity LTO-5 tape is around AUD$60. Looks like I wasn't missing much.
With those sorts of numbers, and an LTO-5 drive costing roughly AUD$2K to a DAT-320 drive at roughly AUD$1K, it's hard to see how DAT could compete against high-capacity tape for a bit more initial outlay, or a removable disk system for even less initial outlay... [but yes, there are some durability issues in that case.]
maybe at enterprise level Tape is a cheap backup solution, but it's sad to see that at a regular joe level it really doesn't stack up that well.
a lot of people do worry about their data, and have vast amounts of it so I'm a bit surprised that high capacity tapes (larger than the largest hard drives) designed for regular complete back-ups using some kind of open future-proof standard don't seem to exist, or be promoted at a consumer level.
if the stuff is so cheap to make, where is it?
High capacity tape DRIVES aren't cheap - the economies of scale come in when you have a library with hundreds or thousands of tapes, most of which are sitting there consuming no power.
So you are using an expensive device to access multiple 'cheap' devices (not that LT0 tapes are that cheap).
In the past, I would have said that the consumer equivalent for backups would be a writeable DVD - but hard drive capacity has of course far outstripped DVD capacity.
You are right though - there would be a market for a durable, high capacity backup solution for home use which could simple be parked on a shelf for years.
Tape remains one of the most cost effective mediums for long term data archiving. I'm not too sure why this is such a surprise really. If you take an LTO6 tape, it's capacity is on par with the largest nearline disks (if you consider compression), speed is pretty decent (160mbps) and is arguably more durable than spinning disk (when stored in the correct conditions). Of course, all depends on RPO/RTO's and the business requirements for BC and DR but tape still has it's place.
I feel that the big "thing" that the tape market has missed is realy home users., while not using as many tapes as companies the possible installbase is huge possibly making up for lack of individual volume through sheer numbers.
As I see it now there is currently no viable way for a home user with alot of data to keep backups and archive copies that is realistic.
To me the "ultimate" system for home use needs to fulfill a few criteria to be worthwile.
1. Physical size. The "unit" must fit inside a standard tower or for an external unit be no bigger then a shoebox.
2. Storage size. Must be sufficiently large that at most a few media units are needed for a full backup of a larger home system.
3 Has to be able to keep archive data.
4. Initial up front cost has to be low.
5. Cost per backup has to be reasonable. Has to be able to keep a few complete backups wihthout serious cost escalation.
6. Has to be "offline", if malware can whipe your backup you might aswell be without one.
7. Backup / restore time has to be reasonable, and require minimal interaction while running.
If for home use we limit ourselves to the following (I might well have missed some)
Optical disc - fails misserably on 2,5,7
Disc (usb style) - while not failing to bad anywhere the combination of wanting more then one backup and cost/backup makes this unatractive
Disc (NAS style) - Same as above but potentially vulnerable to malware on the backuped system.
Cloud - While I'm not fully up to date with costs for home solutions and there ability to rollback changes that has been pushed, it nontheless fails misserably on the speed requirements, an initial backup of 5TB of data using my home ADSL connection with 2 megabit upstream speed is not going to be done anytime soon, and I'm fairly sure no sane person wants to wait for the full recovery of said data either.
Tape - Aces most of the points not relating to cost where it fails misserably on upfront cost.
I fail to see any reason why a LTO tape drive has to have the seriously inflated pricetags thay have today. Sure there may well be significant development cost but that is what volume is there to combat. That leaves only extortionate licensing costs or just the regular corporate markup to warant the pricetag.
A low cost unit would be able to tap into a whole new market.
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