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Ask Slashdot: Personal Tape Drive NAS?
New submitter hey_popey writes "I would like to piggyback on a previous Ask Slashdot question. Do you know of any realistic way to use a tape drive solution at home, not as a backup, but as a regular NAS? I would like, for example, to save the torrents of my Linux distributions on it, and at the same time, play the family videos on a computer. It would seem at a first glance that the transfer rates and capacity of Linear Tape-Open (1.5TB, 280MB/s in 2010) and the functionality of LTFS would allow me to do that, but I don't know the details, or whether this would be economically viable."
The big disadvantage of tapes is that it has long seek times. Not 'long' as in a few times that of a hard disk, but 'long' as in: can take a full minute to do. Access of multiple files on a normal HD is done by reading a meg of the first file, then seeking to the second file and reading a meg, going back to the first file and reading a meg etc. On a tape drive, even when the seek time is only, say, 10 seconds, you'd get a total throughput of 100K/sec that way. And I'm not even talking about the havoc that using it for storage of torrent files wreaks on it: that's a random-access process if I ever saw one, and the seek times on tape would kill your bandwidth very quickly, and probably your tapes too (because of wear&tear).
you're not thinking this through, are you? it's a tape-drive...
No. Just no.
Tape is great for reading or writing sequential data but trying to access random files would suck, which is exectly how it would access files if you are trying to access movies while writing other data to it.
The only way I see it working would be to have a HD or SSD acting as a cache between the tape drive and the network.
These comments are my personal opinions and do not necessarily reflect the opinions of the other voices in my head.
No. Your question has no rational purpose other than to attempt to create a corner in a circular room
As a NAS a tape drive has three flaws--
Cost.
Reliability
Software.
Tape Drives are designed as peripherals that were either reading or writing the tape media. Read/Write is not an option--- ever heard of Seek Time?
you'd need a cache drive in front of it.
the mb/s is ok yes, but that's for linear read/write from the tape.
"While specifications vary somewhat between different drives, a typical LTO-3 drive will have a maximum rewind time of about 80 seconds and an average access time (from beginning of tape) of about 50 seconds.[21][dead link] Note that due to the serpentine writing, rewinding often takes less time than the maximum."
the tape is also only good for 260 full passes.
just buy a hd based nas, archive to tape if you really archive that much stuff. but load it on hd first for gods sake.
world was created 5 seconds before this post as it is.
The determining factor is definitely cost. A tape loader or even just a single tape drive is pretty expensive, even when buying used and provided you have the right equipment to house it if it's not in its own enclosure. The price of media is comparable to physical drives of equal space. Honestly, it would be cheaper and less of a hassle to build a disk-based NAS.
Unless you stuff a large harddisk inbetween as cache, I don't see how you can make this perform anywhere near bearable.
Note that frequent write/delete cycles will fragment tape space like you wouldn't believe (perhaps a weekly tape reorganization job would be in order?).
I used to work on z/OS where using tape for normal storage isn't unheard of; typically files not accessed for a while are moved to a tape robot.
When trying accessing one of those files, it did so by writing the file back to harddisk for actual access.
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The overwhelming issues with latency aside, a 1.5TB (native not compressed) LTO drive will set you back ~1800 USD and you'll need an extra ~100-150 for a SAS controller that can drive it. For that price you can by yourself 24TB of HDD storage (12 x 2TB) with enough money left over for a decent SATA/SAS RAID controller. If you setup a RAID 10 array you'll have 12TB exponentially faster access times and better data security (unless you make copies of every tape).
Have you considered punch cards? You can get a vintange IBM 370 for only a few hundred thousand and a warehouse to store all the punch cards for just several million. Put it in China and you can have a few servants ravage up with forklifts and storage boxes with the cards and scramble to put them in the reader and upload it back to your home media server.
I mean who cares about using a cheap $200 external usb drive like everyone else pretending we somehow live in the 21st century ... pfft
http://saveie6.com/
They are not only useless at home. They are completely useless as a backup solution in the first place. They refuse to read in 95% of their intended usage scenarios, including, but not limited to, incompatible/failed tape drives, missing/obsolete/buggy/outright stupid software, degraded/stretched/torn off tape, mislabeled/misordered media and so on. And then again, they cost $$$$$, because PHB's keep on buying them. And they do, because they like solid-looking stacks of backups. Even if no one prescribing them in the backup plans had ever tried to restore a single file in the last 20 years. Or ever.
Hard disks are good. They are also good for backups. They are cheap, they sell them in the shop down the street, they work 99.99% of their intended usage scenarios, do very well in every other usage scenario, and they can be easily connected to any computer, just to see what's in.
... there used to be a product called "Desktape" made by a company called Optima Software.
Basically it kept a cached (on the system drive) directory listing of all the files on the tape, and then made a (virtual) disk using that directory which was mounted on the desktop (hence the name). The user would perform file transfers with this "disk" in much the same way as he would a real disk, he could copy files to and from it by dragging and dropping, similarly erasing or copying over files. Note that I said file transfers; direct random access to this "disk", while possible, were strongly recommended against because the tape would seek to one block, then seek to the next etc. so, for example, launching an application from the tape was ill-advised. Anyway, when the tape was ejected, the directory would be updated on the tape.
Still it was great because it made backing up very simple (no special utility to run) and this disk would behave just like a real disk so that you could run regular disk utilities on it like "Virtual Disk" (which kept searchable online copies of directory listings of offline volumes).
The software was hardware agnostic which means it could work with a variety of tape drives so maybe it would work with LTO. Alas, the software only ran on pre-OS X Macintoshes and the company is long gone. I would dearly love it if someone could revive this software and make it work with a "modern" OS! Can't someone buy the IP of this company?, surely the development (patents?) is worth something. (I wish there was some sort of law saying that abandoned software like this would, after 5 years, be put in the public domain; of course for this to work the source code would have to be continually archived at, say, the Library of Congress in case of sudden bankruptcy. Not too feasible.)
Did you know you can refrigerate your food by placing it in front of your air-conditioner?
And who needs a stove or oven? Simply wrap your food in your discarded tinfoil hats, and place it on your engine block; by the time you get to the office, breakfast will be ready.
I've also heard you can pound nails with a screwdriver if you adjust your grip...
As a co-worker of mine is fond of saying: "There are no stupid questions. Except for that one..."
PS: A lot of people seem to have the wrong idea about how this guy intends to use it. He's not talking about seeding torrents or installing programs on a fucking tape drive.
I think he means using it as for storing and occasionally reading old torrents or films or whatever, but instead of using a disk drive wants to use a tape drive with a disk drive like FS, so he can burn a linux CD or watch a movie from time to time. It's not a bad idea. It'll cost less than disk drives and still be reasonably durable.
LTO tapes have a durability of about 300 whole passes. Hard disks and SSD's have several orders of magnitude better durability. Note that the poster is trying to use it as active storage, not as archive material.
And frankly, even for archive material I'd trust an offline stored disk for as long as I would a tape (a 30 year stored tape reader would suffer from the same mechanical issues that a disk might after such storage). Either way, you're better off using online maintained redundant storage than hoping anything stuck in a dump'n'forget archive will actually be readable once you want to read it.
While the tapes themselves have a 30+ year shelf life expectancy with minimal data loss, the tape drives do not.
Five years ago, I tried backing up everything at home on a DAT72 tape drive. I have now on 24 tapes redundant backups of everything that will be even readable after i'm dead, but it's useless. After three years, one of the spindle motors of the tape drive burned out. It's not replaceable or fixable. A replacement tape drive on e-Bay (cheaper that the original price) to read back those 24 tapes of ~40Gb each costs now way more than the cost of 3.5" 1 TB sATA HDD.
Tape backup is not price-efficient for home use.
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Come on now, if someone is smart enough to look up the specs for the technology they surely, surely know this is a completely ridiculous suggestion for a home environment.
Yes the mammoth automated tape libraries exist(ed) for huge business over the last 50 years, however a home version which doesn't require user interaction for tape changes is madness, plus, depending on the OS - the system may well want to check / index / scan the files frequently. Is this person proposing using multiple drives? Seriously what's the deal here?
I guess if it's a troll, bravo - it's stupid yet they clearly let it on the site and I as well as others are biting.
If it's not a troll and you're legitimately asking,.... I really don't know what to say,... do you actually want a thought out response to such a ridiculous fucking question?
Editors: you're better than this, I thought anyhow,...
As everyone else, that using a collection of tapes with a single or small number of tape drives is impractical.
Instead, I recommend reading up on hierarchical storage:
http://en.wikipedia.org/wiki/Hierarchical_storage_management/
Also, if you really want a solution which does what you ask for, SamFS may be for you:
http://www.c0t0d0s0.org/archives/4240-Less-known-Solaris-features-SamFS.html/
Bye,
os10000
It'll cost less than disk drives and still be reasonably durable.
That's the problem. Tapes are at best half the price of disks, and the drive is expensive. Next year disks have fallen in price, but the tapes still cost the same, and that just gets worse over time. To maintain a decent tape price it is necessary to switch standard quite often.
Finally! A year of moderation! Ready for 2019?
There are online services that for a reasonable fee will accept your tapes and put them into online storage(or a HD) for you.
I don't read AC A human right
Your argument has some merit, but I've consistently found it not to really hold true for the smaller or mid-sized companies I've worked for.
The "high cost of entry but low maintenance cost" of tape just doesn't always pan out, IMO. For starters, you've always got the issue that the tape media isn't readable by anything except a system configured with one of those expensive tape drives designed to work with that generation and type of tape. That means if you're using those tapes for disaster recovery by storing them off-site, you've got to be sure you can read them back in if/when disaster strikes. If that disaster is, say, a fire in your building that destroys the computer equipment? Now you've got to be sure you've got quick access to a machine capable of restoring the data on those tapes so you can set up replacement systems from it. That means you may have to buy a duplicate, costly tape drive, and store it off-site with the media, or pay an outside firm to do the data recovery for you (because they have the needed equipment to read your tapes for you).
When your off-site data is stored on standard-issue hard drives, you don't need anything more fancy than an external USB hard drive enclosure to get to the data.
(And yeah, I realize you could do the accounting on something like this by claiming those extra costs are part of the "initial expense" instead of the "maintenance" portion.... but either way, you're spending the money.)
And that thing about putting a box of tapes in a panel van and bumpy roads not worrying you? Yeah, I suppose .... but any decent hard drive parks its heads when it's not spinning, and really shouldn't be affected by that sort of vibration. We've had nightly backups running here at two locations for years where the backup media is a consumer-grade SATA hard drive in a removable hot-swap drive tray, and people take them home every night by tossing one in the trunk of their car or truck. I think we've only had 1 drive fail out of the entire 2 week rotation used for both sites after 3 years or so of use. That's well within what you'd expect fro drives that never even get removed and carried around.
Back in the before time, I knew a guy who ran a BBS who came about a DAT drive by some method or another. I assume he stole it from work. Anywho, that was a lot of storage back then and he wanted to use it to store files for the BBS. What he came up with was a caching system where people tagged the files they wanted, the files would be copied from tape to temp storage on the hard drive, would be downloaded by the user, then deleted from the hard drive. I had a similar system for the CD-ROM changer on my multi-line BBS. If someone on line 3 wanted file from Disc_2 and someone on line 1 wanted a file from Disc_7, the poor thing would just thrash back and forth between discs until I added the caching system.
But it's just totally impractical today. I've got a 26tb array for my bulk storage. Even with hard drive prices still a bit inflated, it could be built for $2500 with nice drive cages. $3200 for 39tb using 3tb drives.
An LTO 5 library is going to run you $5000 for just the drive/library. You weren't going to stand there swapping tapes by hand, were you? Another $550ish to fill it with tapes. And that's only 1.5tb gigs per cartridge. (Native capacity is what you should be using for this type of data.) 16*1.5=24tb online for around $5500. Nevermind the cost of the caching system that would be needed just to make it work in even the most crude manner with a minimum of 5 minutes between initial request and the file being available for use. More than double if it spans tapes.
So roughly double the cost for a similar amount of storage with horrendous access times. Sounds like a plan. You should totally do it and report back.