Well, M-Disc is out as bluray for about 2-3 months now. That's 50 GB on double-layer with a promised 1,000 years of lifetime. A practical problem will be (for me at least) that it will be hard to sue them in 500 years if it turns out that the medium doesn't last the promised 1,000 years.

Of course they're not precisely cheap, either, single layer currently going for 8€ the piece, which is more expensive than a 32GB USB stick. It's a start, though.

I honestly feel like storing all my data on DVDs would be a mite bit crazy. That's over 200 4.8GB DVDs just to store a terabyte of data. That's 7 pounds of pure DVDs, almost a foot high (based on some random website). They just don't have the density for viable large-scale backup. Even at smaller scales, flash drives are more efficient in my book.

Thumb drives come in sizes up to 256 GB now-a-days.

Heck, a micro SD card can go over 64 GB .

RAID 5 is a good backup system, but all those SSD hard drives can get very expensive.

Hmm, that M-disc sounds interesting. 50GB sounds good to me, and only been out for a few months? Looks like this post is right in time.

I am thinking though, since computers are coming without disc drives, how would I write to the disc?

I honestly feel like storing all my data on DVDs would be a mite bit crazy. That's over 200 4.8GB DVDs just to store a terabyte of data. That's 7 pounds of pure DVDs, almost a foot high (based on some random website). They just don't have the density for viable large-scale backup. Even at smaller scales, flash drives are more efficient in my book.

Thumb drives come in sizes up to 256 GB now-a-days.

Heck, a micro SD card can go over 64 GB .

RAID 5 is a good backup system, but all those SSD hard drives can get very expensive.

RAID shouldn't be viewed as a "backup" mechanism. It's for redundancy, which is a bit different. It's handy in concert with other redundant systems overall as a backup solution however, which is why I mentioned it.

Why the heck would you use SSDs though? Just use regular HDDs. Hell, as a non-expert, I have to question whether RAID 5 even makes sense at all for SSDs. Do they even have the same failure patterns?

Why the heck would you use SSDs though? Just use regular HDDs. Hell, as a non-expert, I have to question whether RAID 5 even makes sense at all for SSDs. Do they even have the same failure patterns?

1: SSD is not prone to as many failures as HDD

2: SSD is a lot faster than HDD

3: RAID speeds up disc reading/writing

Semi relevant video from 2009

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I am thinking though, since computers are coming without disc drives, how would I write to the disc?

I use a Panasonic 70€ USB writer. Note that not all writers can do M-Disc (needs some kind of high-power laser).

RAID on SSD

Well maybe if you have 10G or 40G ethernet. My 4-disk RAID5 runs at maximum theoretical throughput over gigabit ethernet, give or take a dozen kb/s (actually twice that, since both clients and NAS are wired to the router with two NICs, and use link aggregation, completely saturating two cables). Writing to the RAID doesn't get to saturate the cable, but I doubt SSDs would help much there.

RAID is awesome since if a sector goes poof on a disk, it isn't gone, and if a whole disk poofs, it still works. In theory, that is... if the RAID is able to heal after you replaced a disk without getting another sector or drive failure (which, unluckily, is not at all impossible).

You had better had no power failure during that time or a really good UPS, too. Healing the RAID after adding/replacing a disk takes around 2 hours (assuming 1TB disks, double that for an array of 2TB disks, etc). That is a quite long time during which you're "vulnerable".

But RAID won't protect you from the whole box being destroyed by a thunderstorm (the UPS is supposed to catch that, but who can tell for sure!) or by theft or such, and it won't protect you from being an idiot and deleting a file which you only realize being important the next day.

A backup will protect against that (preferrably on a write-once medium).

Here is my experience. In 2011, there was a major earthquake in Christchurch. My company was relatively lucky. Our office building was damaged beyond repair, but we were allowed in very briefly to get our computers out. We had a stict backup regime on portable hdds taken offsite every day... to someone's house which also suffered major damage. Luckily we were able to retrieve the disks, put the office together in my bosses garage and work remotely for a year while we got back on our feet.

But the FIRST thing I did when we started setting up again was to configure our source control to drop the last good build to Dropbox at every release. That way, even if we had another big shake and it took out everything, at the very least our core IP was safe.

1: SSD is not prone to as many failures as HDD
2: SSD is a lot faster than HDD
3: RAID speeds up disc reading/writing

#1 depends, some SSD drives have faulty firmware that will render the drive unusable much faster than for a hard disk (they basically just stop working for no reason).

Of course that one is simple, just avoid SSDs that have faulty firmware. Is there any general guide regarding which SSD drives tend to be faulty? I imagine that'd be useful (and yeah, I'm curious about that) Also I wonder how common is faulty firmware these days.

Oddly enough the only drives I've actually had issues with so far have been solid states. My first SSD died after about three month's of usage, and I have a Compact Flash card that for some reason dropped its main table on me randomly once (And forced a long annoying data recovery process to get the photos back), and I've been rather iffy about that one since.

Given the price, hard drives seem like the best choice to me. For the cost of storing something on a single SSD, you can store them on multiple hard drives, and in multiple locations.

One of the biggest things that people overlook when it comes to the risk of data loss, is the risk of a logical failure, rather than physical failure. This is why RAID of any kind is and of itself NOT a backup tool. Either malicious software, or just dumb accidents, and a badly configured 'redundancy' system can trash your data just as easily as a drive head crashing will, but in a far worse way. You may not notice that your data is gone, and then happily merge those changes across a poorly designed backup system to multiple drives and locations, and then have no clue that you've just happily destroyed your own data.

I had this problem the other week with some photos. My usual work flow is that photos go on a portable drive after they're captured, have their initial pass of processing/culling done, and then get synced to the home system backup disks on my main computer. The problem was that I got busy after volunteering to shoot an event, and the initial processing was delayed a few days. In that time the photo disk had been attached to my main computer, which I've also been using with a few friends for a research project. Part of that project involves another external drive which we use as a dump-disk for half processed data. We frequently format this drive when we start a new pass on the experiment (Mostly because we have yet to get around to writing in error handling for a full disk on writing...) but that time the project disk was actually upstairs, as I had been poking at some data on my laptop. My friend, who was logging in remotely to the machine, asked on Skype if I was alright with him formatting the project disk and running a new test case. I told him to go ahead and didn't think about it. Awhile later I was sitting at my kitchen table and noticed the project disk...

I've had bad luck with SSDs as well. I've had two (from different manufacturers) die in as many years. Both were fine one day, and gone the next.