![]() Unfortunately, one or more of those things is often not the case, and your offsite tape copy process becomes as mismatched as your initial backup process. That is assuming that your disk target is able to supply a stream fast enough to keep your tape drives happy, and there aren’t any other bottlenecks in the way. If you have your nightly backups stored on disk, it should be possible to get those backups copied over to tape. This is why most people are still using tape to get backups offsite. These can be effective, but they are very costly, and there are a lot of limits to their deduplication abilities - many of which make them cost more to purchase and use. If you’re using such a system, you have to buy an expensive deduplication appliance to make the daily backup small enough to replicate. Tape is still the cheapest way to get data offsite if you are using a traditional backup and recovery system. I agree with this recommendation - any transported tape ought to be encrypted. Even Iron Mountain’s CEO once admitted that it happens at a regular enough interval that all tape should be encrypted. Their have been many incidents involving tapes lost or exposed by offsite vaulting companies like Iron Mountain. If you don’t care about restore speed, then they’re great! It literally makes your restore ten times longer. If you interleave ten backups together during backup, you have to read all ten streams during a restore - and throw away nine of them just to get the one stream you want. It’s better than nothing, but remember that it helps your backups but hurts your restores. Multiplexing is simultaneously interleaving multiple backups together into a single stream in order to create a stream fast enough to keep your tape drive happy.Disk drives are much better suited to the task. Tape drives are simply not the right tool for incoming backups. This wears out the tape and the drive, and is the number one reason behind tape drive failures in most companies. It does this over and over, dragging the tape head back and forth across the read write head in multiple passes. When incoming backups are really slow, and the tape drives want to go very fast, the drive has no choice but to stop, rewind, and start up again.This number is nowhere near 100-200 MB/s. A file-level incremental backup supplies a random level of throughput usually measured in single digits of MegaBytes per second. Most backups are incremental backups, and incremental backups are way too slow.Add compression, and you’re at 100-200 MB/s minimum speed! For example, the slowest an LTO-7 drive can go using LTO-7 media is 79.99 MB/s native. Yes, there are variable speed tape drives, but even the slowest speed they run at is still very fast. In case you didn’t know it, modern tape drives essentially have two speeds: stop and very fast.Tape drive are too fast for incremental backups There are also reasons why you don’t want to use them for your offsite copy, and I’ll look at those, too. Tape is good at some things, but receiving the first copy of your backups isn’t one of them. It’s been this way for a long time, and I’ve been saying so for at least 10 years, in case anyone thinks I’ve been swayed by my current employer. Specifically, this article is about why modern tape drives are a really bad choice to store the initial copy of your backups. ![]()
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