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Magnetic Tape Storage - IEEE Article

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DaveLembke:
Found this interesting this morning to read. I had thought that they moved on from magnetic tape onto other things like holographic storage which was mentioned a few years ago as the future for massive amounts of data stored densly into a small area etc. I guess magnetic tape due to its low cost and data density is still going strong!  :)

At the tail end of my IT Career with my prior employer we were storing data on multiple RAID 5 drives in multiple locations and at timed intervals about once every 15 minutes, data was updated between the 7 locations to mirror each other over T1 connections at 6 of 7 locations and a private DSL bridge to 1 remote location with Copperlink 2.4mbps/2.4mbps Modems. In addition to this we had shadow copy enabled so that if someone accidentally overwrote something important it was able to be recovered of its prior form. The data we had was large like 300GB of our 1TB storage capacity, but the most critical of data ( accounting data and e-mail ) was less than 8GB so we were using an old tape drive for daily backups which was in a rotation that the following weeks data was overwriting the prior weeks data, and a monthly backup was stored offsite for 7 years at 12 tapes per year sent to safe storage offsite.

I thought that tapes were trailing in storage capacity to that of drives, but to my surprise far more data can be stored on a modern tape than todays drives.  :o I didnt think that the data density of tapes was matched to that of drives and the simple fact that tapes have more storage surface area than platters would make them that much better for mass data storage.

https://spectrum.ieee.org/computing/hardware/why-the-future-of-data-storage-is-still-magnetic-tape

Mark.:
the only problem with mag tapes has always been their sequential access, about from that - they pretty much rock.
but like you, I thought they were all but dead.
certainly would be surprised if new mainframe sites where still using them.

camerongray:
Yeah, I've seen quite a few tape drives kicking around in a datacenter that I'm sometimes in, including brand new ones being installed.  They are still a pretty good option for storing backups due to the capacity of modern tapes (up to 12tb uncompressed for modern LTO-8 tapes).  Performance pretty slow, especially random performance (if you want any sort of random access, forget about tape) but they work out pretty well for long term backups where you would be restoring a large amount of data in one big chunk rather than pulling off individual files.

The tapes tend to work out a fair bit cheaper than hard drives of the same capacity.  The drives are generally quite expensive so for small amounts of data you'd probably find hard drives to be cheaper but they can work great for things like offsite/daily backups onto a stack of tapes or, for really large capacity, a tape library can be used to automatically feed tapes into a drive.  Compared to using a large RAID array to hold backups, you also get the advantage of lower power consumption (you are just powering the tape drive when you are writing to it instead of having to power an entire RAID array 24/7) and don't have to worry about drives failing in an array - if your tape drive fails, you won't lose the data stored on the tapes and the tapes themselves are incredibly reliable.  It's also not a bad idea to have backups stored on a pile of tapes that are completely offline rather than storing them on a backup server connected to the network - it's going to be pretty hard to accidentally (or maliciously) wipe out backups if they are stored on tapes sitting on a shelf in a secure location!

BC_Programmer:
Some of the larger ones nowadays go to 12TB. I had a Tape Drive in a 386 Server Tower which I never used and never had drivers for so I don't actually know what it was. I suspect it was a Travan.

Some other advantages:

-The mechanism is a bit simpler so they are often more reliable, especially direct drive models. (The Tapes themselves are of course susceptible to magnetic interference like a standard magnetic disk)

-capacity wise, for removable media, there simply is no competition. And this is an advantage not only for backups but for a lot of other purposes. If you need to move a lot of data across the country for example, you may find it is faster to just back up to the tape, drive there, and restore it, rather than try to copy the data over the Internet.

camerongray:

--- Quote from: BC_Programmer on September 01, 2018, 04:39:51 PM ---If you need to move a lot of data across the country for example, you may find it is faster to just back up to the tape, drive there, and restore it, rather than try to copy the data over the Internet.

--- End quote ---
Yep - "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway." - Andrew S. Tanenbaum.

Amazon even provide pretty much this as a service for migrating data in and out of AWS.  They have their "Snowball" service (https://aws.amazon.com/snowball/) where they ship you what is essentially a very powerful, rugged, 50 or 80tb NAS which you can load your data onto and then ship back to them to have it ingested into AWS S3 storage.  They even offer "AWS Snowmobile" where they literally deliver a truck full of storage to a client's datacenter to be filled with data which is then taken away and loaded into AWS - https://aws.amazon.com/snowmobile/

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