Trying to think of best solution re:RAID arrays

RAID doesn't protect your data from most threats (such as the viruses you mentioned), therefore backup is the most important thing for you to get right. Figure out how many hours or days of work you can afford to loose and that will help to determine what you need in terms of backup media. Once you know that, you'll have a better idea of what disks you'll have for your RAID solution.

Remember that good backup means two offline copies of your data, one of which is offsite.

siminlal gave you good advice.

The value of raid-1 and it's variants like raid-5 for protecting data is that you can recover from a hard drive failure quickly.
It is for servers that can't afford any down time.
Recovery from a hard drive failure is just moments.
Fortunately hard drives do not fail often.
Mean time to failure is claimed to be on the order of 1,000,000 hours.(100 years)
Raid-1 does not protect you from other types of losses such as viruses,
software errors,raid controller failure, operator error, or fire...etc.
For that, you need EXTERNAL backup.
If you have external backup, and can afford some recovery time, then you don't need raid-1.

In a similar vein, There is generally no real world(vs. synthetic transfer rate benchmarks) performance advantage to raid of any kind.
Go to www.storagereview.com at this link: http://faq.storagereview.com/tiki-index.php?page=Single...
There are some specific applications that will benefit, but
gaming is not one of them. Even if you have an application which reads one input file sequentially, and writes
it out, you will perform about as well by putting the input on one drive, and the output on the other.

Don't laugh: we got burned so badly by a bad virus
many years ago, that we've built a machine that
we only switch ON to do backups across our LAN,
then we switch it OFF.

We confirmed that THE BEST virus protection
is a machine that has no electricity flowing
though it!  


This also prolongs its useful life, because it only
runs a small percentage of clock time.


MRFS

OS and its application does not need to be backed up (or imaged). If it gets infected by virus then do a full nuke -> clean install, can be done fairly quickly and painless, but only if you have done your homework.

What you can do is go with 4x1TB RAID 10, giving you 2TB of space. Make a ~100GB partition for the OS to install on. Use the remaining space to store data, installables and latest drivers. Use folder shortcuts to folders on the other partition(s) and never store anything personal on main partition e.g. C:\Users\[username]\Documents <-should not ever exist!
Use the external drive to do periodic backup/syncing of priority #1 files.

> OS and its application does not need to be backed up (or imaged).

Not so, if one has installed and integrated numerous
third-party software packages, not to mention all of the
user-specific settings in each discrete software package.

BEST WAY is to image your OS partition e.g. with Symantec's GHOST
or Acronis True Image, AND keep your data on separate, NON-OS partition(s):

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
(out of stock: should tell you something  


p.s. GHOST has saved us literally hundreds of hours of restore time.
We routinely run GHOST after "Windows Update Tuesday", and
copy the image file to every available partition in our disk farm.

If a partition is small, we overwrite the image file;
if the partition is large, we just increment a suffix e.g. images.001, images.002
and so on. Then, after we have accumulated about 10 such serial versions,
we just delete the older ones. Disk space is so cheap now, it pays
to keep several recent versions around, for the sake of redundancy.

Then, there was the Windows Update that had a small glitch in it,
which stopped our mouse from working: we just backed up
one "images.xxx" version and we were back in business in
about 15 minutes.


MRFS

I totally agree, it usually takes me more than a week to get everything back to normal if I have to re-install, and even then I often run across odds and ends that still need tweaking from time to time.

MRFS, do you have a preference for Acronis or GHOST? I have a good file-based backup scheme, but I'm looking for something that I can boot from a CD/DVD and do a simple OS image backup or restore using an external USB hard disk. I've had a quick try at PING but haven't had any success with it so far...

I have had great success with both Acronis and Ghost. I have more experience with Ghost, but I would not hesitate to recommend either. Both will do what you are asking for, and both achieve it fairly painlessly. I would very slightly lean towards Norton Ghost, but you really can't go wrong either way.

Hard Drive reliability is getting worse and worse. Look at the charts over at storagereview.com to confirm this. Whether it's due to trying to squeeze more and more out of the technology or the push to get ever cheaper and cheaper, is hard to say. Looking at the Raptor WD 1500 for example, out of 210 drives in the survey.....

5 were DOA
2 died 1st month
3 died by 3rd month
12 died in 1st year
12 died in 2nd year
14 died in 3d year
6 owners stopped using before 3 years for whatever reason

54 outta 210 or 26% were reported as not lasting 3 years ....that's an astounding failure rate and that doesn't even take into account that people who entered the survey say after a year, never reported back a year or so later to say that the drive had failed.

As for the original question, I think it depend son your situation. Obviously if you auto backup to an NAS or file server data integrity is less of an issue. On a stand alone box, I would think (3) 7200.12's at $270 makes an affordable, fast and safe installation. However with HD's getting so big, experts are saying that the odds of stray bit messing up things are resulting in unacceptable risks:

VBhttp://www.tomshardware.com/news/RAID-5-Doomed-2009,652...

"The problem comes from the increasingly tight data density packed onto drive platters. Using traditional means, bit magnetic poles can often leak their polarity onto other adjacent bits, causing a switch in an otherwise normal bit. Manufacturers have switched to perpendicular recording methods to avoid such problems and increase density, but even this method has its physical limits. Manufacturers will have to find more creative solutions down the road if drives are going to exceed 2TB in size."

At 1 TB tho, and outside of a server application I think the risk is much lower. I keep all my data on an NAS but that's backed up to a file server and my laptop in compressed format daily (fire would take both NAS and file server out) and to DVD's monthly.

@JackNaylorPE:
Sobering statistics, if representative. Do you know how the samples were taken? It seems to me that many times we only hear about the failures by those who were burnt, and not about those who had no reason to complain.

Surveys that rely on voluntary participation are notoriously skewed because people with problems have more motivation to report them than people who don't.

I love acronis. Howerever certain versions of Vista and all versions of Windows 7 have very good simple image software built right in. Probably the best Windows 7 feature I like is the backups on all editions.

You can boot to your image from the boot manager, or from a disc if you bother to make one.

Acronis if your Os doesnt support built in imaging, but if your on Windows 7 you have everything you need.

It must be kept in mind that most of those in the survey were registered well before they failed. We register our drives at the 3 month old point....though the site's owners seem to have "lost interest" of late and it's not getting the participation it once did.

The links below show as many as 10% and even 50% failure rates with certain drives.

http://blog.godshell.com/blog/index.php?/archives/87-Ha...
http://blog.godshell.com/blog/index.php?/archives/87-Ha...
http://www.computerworlduk.com/technology/storage/hardw...
http://www.prostructure.com/blog/2008/07/07/hard-drives...
http://www.tomshardware.com/forum/29084-35-toshiba-6100...

All of the builds we've had over the years (61st now underway) I can not remember a failure other than, two CD-ROM's, 1 DVD-RW, 1 PSU (undersized for its usage, replaced 350 with a 650) and maybe a case fan or two .... and no less than 20 HD's. Was telling my father about the discussion and he noted something I wasn't aware of......His NT server went thru 2 sets of HD's in it's 1st three years and then has had no failures in last 8 years. That's a 15k rpm SCSI box w/ HD's running 24/7. After the 2nd replacement, they were moved from 3/5" bays to 5.25" bays with HD coolers.

But we are all skewed by our own experience. Weather, build quality, case temperature, on / off cycles all figure into HD reliability and all vary by installation.

I have Windows Vista Ultimate as my OS if I do a complete PC Backup will that backup everything i.e. if I complete this task onto an external Hard Drive am I covered as far as recovering lost data from hard drive failure/virus etc?

If this is the case then I would probably look at just using a RAID0 setup so that I can increase my storage capacity and then as advised get 2 external HD one for home and one for another location in case of fire theft etc. (and these should always be unplugged other than during backup correct?).

I don't mind a bit of downtime if I have to replace a HD so long as I can restore the system to it's prior state. So this is what I am thinking now.
2x 1TB HD in Raid 0 (Can I do a backup of 2 drives in RAID0 to an external HD and what will recovery be like?)
1x 1.5TB External Drive at home (I read somewhere that it helps to have about 25% of Hard Drive space free)
1x 1.5TB External Drive at office or other location

So what do you think as mentioned downtime isn't an issue just want to be safeguarded from losing any data/information.

Thanks for all the great comments and guidance and again thanks in advance for any further comments

That is actually quite nifty. I haven't paid any attention to the Windows 7 backup because I wanted a solution that was compatible with XP, but the disk imaging thing looks like it might be just what I need for OS disk backup.

Thanks for pointing this out!