Another simple way of thinking of a backup is that it is a static image of a set of data at a specific time and date. You can be confident that it never changes, and the various levels of complexity of a backup system can provide what is in effect a rolling series of images which allow you to revert your system to a given point in the past, depending on what backup solution you use. You can never do this using just RAID as you will only ever have (if things haven't gone completely pear-shaped) the state of the data at the present time. Or you might simply lose the lot if, for example, you have a serious data infection, or someone has nicked your computer. :lol:

As a practical example of what I have written, I have only this week successfully restored my own laptop to full working order following a week of data problems. This was simply achieved using a relatively recent backup and a set of simple folder copies to an external drive which I do more frequently for my most important documents as a crude form of incremental backup. With only a RAID array, and no backup file, I would have been totally scuppered.

Yeah, dead easy for a demented, drunken, crippled pensioner like me !! 😢 😢 :thumbdown: :thumbdown: :glare: :glare: :sneaky: :sneaky: 😞 :(

and thats why i tell people to buy a mac and a big external drive. It may** be a bit more expensive initially but its worth it for time machine alone.
If your hardware dies buy a new one point it at the back and then a few hours later you have an exact duplicate of the old machine.
Accidentally delete a file and you can find it pretty quickly and see its the right thing before you restore

** bought at the right its usually cheaper for the same hardware.

Oh raid any level != backup, though it can protect you from *some* failures that would have required a new disk.

wont protect you when your os decides to corrupt the file system,
when you accidentally remove the wrong directory etc. etc.

IMHO Hardware raid is a pain, if you dont have an exact duplicate of the hardware raid card. Once had a machine that the card died though the disks were ok.

These days I prefer software raid and and external backup and for really important stuff a backup to a could machine too!

http://en.wikipedia.org/wiki/Backup 

The first purpose of a backup is to recover data after it's loss. Something RAID1 will do.
A secondary purpose is to recover data from an earlier time. Not something that RAID1 will do.

I know this (it's pretty bleedin' obvious).

But it does mean that RAID1 is a backup solution.

It might not be appropriate for all-singing all-dancing high-availability e-commerce solutions.

However, for storing a few photos, the loss of which would hardly be a calamity, it is an improvement over no backup at all, and a darn sight easier than cutting optical media every so often.

BTW, I wonder how many people 'backup' onto optical media, only to find that they can't read it when recovery time comes!!

Chris.

CD and DVD back-ups are a catastrophe just waiting to happen -usually when you try to read them on another PC.

Same applies to external hard drives to a lesser extent.

Quite a few pro photographers I know create at least two back-ups of their images on different drives right from the start - Photoshop Lightroom is a great help here, you can tell it to write back-ups to another disk while importing files.

Not sure about storing images in the Cloud, haven't looked very closely at that yet, but I'm sure there are security issues which I can't afford for my translation work.

As to system back-ups, I leave it to Acronis True Image to do it on a regular basis and write them to two different external drives. I've had my PC "rescued" three times by this method after system crashes and f'ed hard drives!!!

When you've paid for the recovery of data from a knackered drive in the past, I can assure you all that a decent software back-up solution pays for itself with the first back-up you make.

Cheers

Not sure about storing images in the Cloud, haven't looked very closely at that yet, but I'm sure there are security issues which I can't afford for my translation work.

I'm starting to come around to the idea of cloud storage, certainly from the point of physical security. We already entrust our most important financial and personal information to online storage with banks, the NHS etc.

For commercial confidentiality there must be reservations, but any data piracy or unfair practice would be fatally damaging to user confidence.

So far I can trust google docs not to spill tea in my drive, or lose a memory stick, or leave my data on a train etc. The only thing that stops me uploading 74gb of mining photographs is time.

Not for all uses or everyone, but it's quite a revelation being able to move between computers and have your data available from anywhere without a thought.

CD and DVD back-ups are a catastrophe just waiting to happen

If you just do a single backup, and leave it... indeed they can be problematic. I use a system where I burn a copy every x number of weeks. When I get to a predefined number (10 at the moment), I drop the first disc burned from the archive, another added, the second drops off, and so on. I can see one bad disc, but all of them? Not likely.

You can never really *totally* eliminate potential data loss, but You can get it down to probabilities that are so small, it's almost impossible to happen. It's removing that last bit of probability that gets expensive.

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http://en.wikipedia.org/wiki/Backup

The first purpose of a backup is to recover data after it's loss. Something RAID1 will do.

Something that RAID will only do if the cause of the loss is a failed drive. Period.
Now what about the other things that can cause your data to corrupt or disappear? Ask any support team and they will tell you that failed drives might be common, but there are other reasons for data loss. I hope you never find something you value becomes irretrievable because you thought that RAID would be sufficient.
😢

Come on! High capacity external drives really aren't that expensive and running a simple back up onto one now and again is not so difficult to do.

This discussion reminds me of the three little pigs. Each one thought his house was good enough but when the big bad wolf of computer failure came along, only the one with the brick house was safe.

Apologies folks; I was getting mixed up with someting else I was doing there, and Old Bushmills doesn't help 😞 ::)

The problem was a back up that was not being allowed by Windows. There was a message about a global catalogue error and a code number. After many try this and try that attempts, disc checks and scans and so on, the offer of a phone Microsoft option to restore the catalogue will seem attractive, rather than have a drive you cannot back up; But that is long winded and doesn't always work.
The crux of this fix is in the fact that you con your PC into thinking (!) that it is backing up from another PC so it does not look for the catalogue code, and back-up goes ahead without any problems. :thumbsup:

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