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42

For me, the single biggest argument in favour of tape is that doubling your storage capacity is cheap. That is, to go from 1TB of HDD storage to 2TB is the same as going from nothing to that first TB. With tape, you pay a large premium for the drive, but storage after that is comparitively cheap. You don't have to have lengthy budget meetings about ...


25

The main advantage of tapes is that it's easy to put them into a rotation scheme and store them off-site for long term backup. You can do the same with disks, but usually they're not that easily fitted into a rotation cycle, and you'll have to store them carefully to avoid damaging them (same goes for tape as well of course, but they're easier to handle).


24

Data retention - if you put a disk and a tape with the same data on it in the same physical location it should last a lot longer on tape than on disk - potentially by an order of magnitude. Also tapes are generally better at dealing with the rigors of being shipped from primary to secondary/off-site data centers multiple times.


15

Tapes don't compare with disk quite like that. Tapes are for backing up, and they compare more with deduplicated and replicated disk like Data Domain, or optical media. The main reason for tape backups is that it's cheap. You can afford to store 10 full copies, even though you don't really need them, because the media is so affordable. The next main reason ...


15

Can I expect that after [10 years] the data would be preserved as well [on an SSD as on] a tape? No. OK, so strictly speaking, I have no solid scientific evidence for that statement. But on the other hand, nobody has solid evidence for the opposite position either. NVRAM has been thoroughly tested on its own. But modeling all failure cases for an ...


14

Deduplication is where you look at the content of a data set, note all the duplicate bits that are present, and store the data just once, replacing all those otherwise copies of data with a pointer back to the one copy. It is particularly helpful with backups because when you back up things like servers so much of the data is the same. Imagine, for instance, ...


13

Consider this situation: You drop a box with 6 months worth of backups down the stairs. If these are tapes in their cases, you pick the box back up and continue on your way. If they are disks, you just lost 6 months worth of backups and you'll probably be job hunting. It's common practice for couriers to take tapes offsite daily and then return them later. ...


10

That is generic guidance. Specific guidance is much better. The big questions you need to have an answer to before you start setting up your backup retention schedule is: How much data am I willing to lose, and how long am I willing to take to recover what I can? Tape backup is near the bottom of the backup/disaster-recovery hierarchy. Very roughly, ...


9

In addition to all the above, there is generally "less stuff to fail" with a tape. It's a very simple device, and you don't have to worry about the onboard electronics (the drive controller with a disk, even SSD). Additionally, their storage and transport requirements are generally a bit looser. They can be subjected to heat and humidity swings as well as ...


9

Great question! Whilst I would say that yes you should test them, I'd say that testing the tapes/drives in themselves is important what is much more vital is testing the end to end restoration process. I can't recommend enough regular full system restorations and service testing, it's the only way to know for sure that the entire system is doing what you ...


8

Is your colleague a Windows guy? Because on Windows, there is the a (for archive) attribute which is set whenever a file is modified and is supposed to be cleared when a backup program backs it up. On Unix/Linux, backup programs normally use the ctime/mtime values of a file do decide if they need to backup the file - if the time is newer than in the ...


8

I looked long and hard at RDX drives and specified the embedded RDX units in a couple of Fujitsu servers I bought. Here's what I found: Microsoft native backup does not play nicely with RDX, because of the status of removable drives in MS disk management. As a result if you run Windows native backup (e.g. 2008 r2) you cannot send incremental backups to ...


7

Typically, if you care about recovering your data after a disaster in an acceptable amount of time, full backups are done regularly (weekly, bi-weekly, whatever) and incrementals or differentials are done daily. Differentials will allow you do do a full recovery in three steps: Restore the latest full (which will only be a week or two old). Restore the ...


7

As an asdide, note that 100MB/min is far below the minimum speed for tape streaming with LTO 3, so you're probably losing a fair amount of capacity with the tape stopping and starting (ie you're probably getting better than 1.5:1 compression, but this is lost in gaps in the data on the tape). This will probably be rather worse with LTO 4, as I think the ...


7

Yes. It's not just a vendor touted compatibility, it's a requirement that's tested as part of the LTO Ultrium certification process. All LTO-4 drives must read LTO-2/LTO-3 and write LTO-3. Specifically see questions 27 and 28 of the LTO FAQ. That said, I've had no problems moving LTO-3 tapes between my Exabyte Magnum 224 (aka Tanberg Data T24) ...


6

I have restored LTO3 tapes that were written to on an LTO4 device. I used an LTO3 device to do the restore and actually had no problems. The tape was only ever used in the LTO4 drive tho and hadnt been appended to from an LTO3 device.


6

The first thing i would suggest is to run a cleaning tape through it at least once - possibly twice it'd bet there is a decent amount of dust on the tape heads. Which would cause symptoms like what you are describing. Also have you tried a different tape? There might be somethign wrong with the tape. Are there any logs on the backup machine as far as scsi ...


6

About a year ago I switched the system at my office to a rotating pool of about 80 LTO4 tapes and have only had one tape fail - it was physically dropped though. The rest of the tapes go through backup/restore/verify cycles and have never had an error. Prior to that we used over 200 LTO2 tapes and had only a single error in the two years I was with the ...


6

Very good questions. I too would like to see good answers from people who know more about this than I do. :-) 3 If the key is lost, we've effectively lost all of our backups Precisely, which is why many or most people don't use encrypted backups. One possible way to go is to build a couple of "lifeboats", i.e. packages with install media, usernames ...


6

Personally I trust tapes for long term storage more than I trust hard drives. Also, unless my math is wrong, The cost to store data on tapes is much cheaper than hard drives. I can store up to 400GB of compressed data on an LTO2 tape for $35.00 while an external hard drive with that capacity will cost roughly twice that.


6

You're going to spend some money on a decent tape drive, but adding storage (media) is an incremental cost, and, as you've read, properly handled and stored tape has a great archival storage lifetime. Tape-based backup systems work very well if it's well managed and maintained. Tape is expensive, and I've love to see a hard disk based system that is ...


6

Don't try and do it yourself. You should be using a program such as amanda or bacula to manage your backups. Use amanda when you don't have a tape library. Use bacula when you have a tape library available. mini rant follows Sure, just using dump or tar works and is simple. How easy is it to restore a certain file from a week ago? A month ago? How do ...


6

Tape drives are designed to be in server hardware with correct cooling and air flow setups. I would suggest you check the internal cooling arrangements especially in area of the tape drive and address this. But I have just checked our tape drives and they are warm but these are in s a tape ibrary.


6

This is way too hot, there are always parts in any computer that would get too hot (CPU/GPU normally) but there's obviously an airflow problem with your server/'PC'. I'd get it unplugged as soon as you can and look to place it in something with appropriately cooled. Edit - looking at their spec that particular drive isn't supposed to go over 40C/104F - so ...


6

Shoe-shining refers to the tape drive stopping and rewinding due to an empty data buffer or inconsistent incoming data stream. This was a problem with older DLT drives. LTO drives shouldn't experience shoeshining. The LTO format/standard was partially designed to eliminate this behavior. HP drives, in particular, have a variable write speed to help reduce ...


6

Tapes are a serial access (as opposed to random access) medium. Miniature pixies engrave each bit onto a tiny section of the physical media; they can't be everywhere on the tape at once so they have to do the work in order. The Wikipedia article on tape storage is a good resource for general questions. Your question needs far more detail (the specific ...


6

I agree. Iron Mountain is everyone's industry standard. They are reasonably "cheap," feature "possession tracking" (everyone that handles them signs off on the handling), and operate nationally across the U.S. Other methods would include storing them in a trusty employee's (like COO for instance) house in a "fireproof" safe that's specifically designed ...


5

(what mailq said) plus: Doing incremental forever is not common practice with tapes, as you can lose the tape with full backup on it and render your entire backup useless. The shift right now is to do full backup + incermental forever against disk backup with deduplication.. this can basically run forever, and you normally run RAID6 in the bottom wich can ...


5

I mean, on LTO tapes they guarantee data integrability for 30 years. I strongly suspect there is no meaningful "guarantee." If you need to restore from tape and the tape turns out to be bad and your company loses $10M during the extra downtime or goes out of business completely, what is the tape provider going to do? Nothing. Monthly fulls are valuable ...


5

What MIGHT work is to use a secondary IDE controller and use PCI passthrough (which is available on ESXi with selected host hardware, and with Xen although that might imply having to use paravirtualized guests).



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