Travel Technology - What's the rationale for running RAID for home PC users?

It seems a lot of home PC users are running RAID in various flavors and configuration, according to online forums / blogs I read.

I'm struggling to understand why people do that.

I have 7 PCs I manage at home (3 laptops / 4 desktops) and I have never felt the need to run RAID, so wondering if there's some benefit I'm missing.

For my needs, I use Acronis True Image to back up my PC's images. The images and data are stored via my NAS (Airlink NAS 250 which is a fantastic home NAS solution), as well as redundantly backed up to large 1TB USB drive and various flash drives for really critical data.

RAID is not a back up solution, so if any of my PCs crash due to hard drive failure, all I need to do is replace the hard drive and restore up my Acronis Image, and voila I'm back in business in about 20-30 minutes.

So I don't understand how using RAID can benefit me, considering that it's not a back up solution, and the extra wear / tear / heat / power use of an extra hard drive for each PC seems to be a waste.

Finally, I'd like to add that I would love to have RAID for my laptops, where it's needed most because of the fact that my laptops are the only ones to have suffered catastrophic hard drive failure, but due to the cramped nature of laptops, it's impractical to run RAID.

So why is RAID needed at home (if you're not running web servers / VPNs etc)?

RAID capability is provided because it is cheap to do so. Thus the device that offers RAID appears to be a better product that one that does not. As in most cases marketing considerations are dominant.

In your case you do not need RAID it seems with your setup. I do something similar.

However, RAID 1 and 5 are backup solutions, just not offsite backup. RAID 0 is the only one that does not offer that.

Thanks for the info. I don't consider RAID 1 a true back up solution, because if your PC is infected by viruses and deletes your files, or your files get corrupted due to various software causes, the data on both RAID partitions are affected. I consider back up to be a set of data that can not be affected by problems on the PC itself.

I'm not familiar with RAID 5 so maybe it could be a back up solution.

It's a real shame that RAID is not available as a self-contained solution for laptops as that is where it is most needed. Maybe in the future with SSDs getting cheaper / smaller, RAID could be used to make laptops more reliable.

I use Raid 0 so I can have a 2TB disk which shows up as 1 drive. This is useful as I store my Films/Videos/Music on the drive, and this is accessed via my Media Centre PC.

If any of the drives fail, I'm stuffed, but I have backups of anything important such as photos and music. If I lose the films/videos, I'm not too bothered.

Cheers,
Rick

I'm not familiar with RAID 5 so maybe it could be a back up solution.
It's not. No RAID ever replaces backups - you already named the reasons.
RAID5 uses one the space of one of your hard drives for parity information (distributed over all drives). So you can use as many hard drives as you like, loose the space of one and the data is not affected if one of the hard drives crashes.

Toshiba, does, or at least did, offer dual hard drive laptops with RAID drivers

... RAID 1 and 5 are backup solutions...

I'd disagree with that. RAID solutions provide redundancy and thus a degree of fault tolerance.

However, fault tolerance is not backup.

I run raid 1 for fault tolerance (and some degree of read improvement). Not for "backup."

some people (maybe wrong / maybe misnomer) used to say RAID was redundant array of INEXPENSIVE disks.

Given that disks are so cheap, its not a large price to pay for the uptime

So there is no love for Drobo (http://www.drobo.com) here? It's a valid backup solution built on top of RAID capabilities.

As long as the RAID array is not your primary disk, I do not see why the Drobo or products like it are not "backup" solutions.

If it's not permanently connected to the computer, it can be of course used to store backups.

So there is no love for Drobo (http://www.drobo.com) here? It's a valid backup solution built on top of RAID capabilities.

As long as the RAID array is not your primary disk, I do not see why the Drobo or products like it are not "backup" solutions.

The disk technology involved in a backup solution is rather irrelevant, so long as it is an additional copy of the production data. Simply using RAID on the production data volume doesn't provide a backup; it provides fault tolerance. Using RAID on the backup platform arguably improves the quality of the backup as then the backup has fault tolerance, too. But just running your production data using a RAID-based volume does not actually provide you with a backup.

Actually, RAID-1 and RAID-5 provide a first line of defense in the face of hardware failure. It doesn't replace a backup, as most other folks have pointed out. They are, after all, mounted in the same cabinet (generally) and therefore are prone to destruction in the event of fire, flood, lightning strike, etc.

The idea behind RAID is to avoid downtime by having redundancy. Most RAID solutions will allow the hot-swapping (no need to take down the RAID array) of a dead drive for a fresh drive in the event of a failure.

In a serious data center, RAID (or a variation thereof) is always used in addition to a backup solution, preferably off-site (by that I mean that the back up media is stored off-site - but not necessarily performed off-site).

For people that run home-based businesses, a RAID-1 or 5, in addition with daily backup (or weekly, depending on the needs of the business) will cover the majority of catastrophic failures - provided that the daily backup is kept at a remote location and not on the same desk as the RAID , in case of a fire :D

As far as RAID-1 or RAID-5, generally RAID-1 is seen as better performing since there is no processing required to mirror the data (it's a block-to-block transfer with very little calculation involved - if any). It does require more drive space (2:1 for RAID-1) and therefore costs more, but with the current drive prices, cost is not that much of an issue right now.

Bottom line: "Do I need a RAID configuration?' - the main answer is: "It depends if you can live with some down time in the event of a hardware failure". For John Doe who stores MP3's/videos/etc on his drive(s), usually a day or two of down time is not a big deal. Also, "It depends on the cost". If you can get a 2TB (1TB RAID-1) HD for 249$ and that it fits your budget, it certainly won't hurt to have it. :)

HTSC

The disk technology involved in a backup solution is rather irrelevant, so long as it is an additional copy of the production data. Simply using RAID on the production data volume doesn't provide a backup; it provides fault tolerance. Using RAID on the backup platform arguably improves the quality of the backup as then the backup has fault tolerance, too. But just running your production data using a RAID-based volume does not actually provide you with a backup.

That's kind of my point. If people are not using RAID arrays as their primary disks then it doesn't matter if it's their backup solution.

As far as RAID-1 or RAID-5, generally RAID-1 is seen as better performing since there is no processing required to mirror the data (it's a block-to-block transfer with very little calculation involved - if any). It does require more drive space (2:1 for RAID-1) and therefore costs more, but with the current drive prices, cost is not that much of an issue right now.

A quibble:

That entirely depends upon the controller and disk configuration. In the absence of duplexed controllers and/or a controller implementation that will read from both sides (older ones don't) you don't gain anything on the read side and lose on the write side.

RAID-5, OTOH, will usually be middlin to good on the read side, but absolutely suck large rocks thru a small straw on the write side. Frankly, I don't know that one would notice this in most home applications, but I also don't have 5TB of disk sitting on the home network.

For home purposes, I think RAID-1 is the way to go, simply because the odds of finding a good/fast RAID-5 controller without paying thru the nose is minimal.

RAID is used for several things: redundancy, performance, and creating large logical units of storage.

In terms of performance, different types of RAID offer differ advantages. Some provide faster reads, some faster writes and some both. It can also mean slower performance depending upon the use.

RAID is greatly misused on the end user desktop. RAID-0, for instance, is commonly misused by people who would be better off just buying a faster hard drive. RAID-0 increases your chance of losing data close to tenfold. Data is shared across both (or more) drives and should one fail, all of the data is lost. Also, the data on the drives can become corrupted. There's almost never a reason for an end user to use RAID-0 unless they are doing professional video work. In such cases, you'd probably want to go to RAID-10.

Some good uses of RAID on a desktop are RAID-1 and RAID-5. The first lets you have a single hard drive failure and your system will keep running without a blink. Your reads will be slower, but not incredibly so. Many people use RAID-5 for media storage for things like an home theater PC. It lets you essentially create one very large hard drive. It does have its own disadvantages though.

RAID is not a backup solution. It's a redundancy solution.

My question for UALOneKPlus is what will you do in the case of an electric surge or fire. You'd lose all data. You shouldn't forget about that case. Having multiple copies of data is only truly good if they're not all in the one place.

That's very true. Most folks won't notice a whole lot of performance difference on RAID-5 vs RAID-1.

Frankly, I don't know that one would notice this in most home applications

I agree 100% there. I also like RAID-1 because it's generally simpler than RAID-5 and requires less physical devices.
For home purposes, I think RAID-1 is the way to go, simply because the odds of finding a good/fast RAID-5 controller without paying thru the nose is minimal.

You'll find that this discussion will get to a point where recommendations are made for a level of professionalism that exceeds that of simple home users... It always ends up like that :)

HTSC

I think there are a lot of people out there who are looking for transparent, painless backup solutions and who are misled into believing that RAID is a backup solution.

For example, my sister is a photographer. I've been trying to help her set up a reliable archival and backup system: an archive for storing all her photos that don't fit on her primary computer, and a backup to make sure there's at least one extra copy of everything (preferably offsite) in case something happens to her computer and/or the archive.

She takes classes at a major photography school and while we were brainstorming ideas she sent me her notes from a lecture one of the professors gave on digital photography technology. I was shocked when he got to "how to store your photos" and recommended simply buying an external hard drive array with RAID1 and keeping everything on it, because "then you have two copies."

I've since had conversations with a number of my sister's photog friends and colleagues, and was surprised to learn that almost none of them have real backup systems in place. Most have their photos haphazardly scattered across multiple external hard drives, but they have no systematic backup system in place to keep everything backed up in real time. So when somebody tells them they can just buy a RAID drive and it'll magically keep everything backed up without them doing anything, they don't ask any questions and just go with it, when what they really need is something very, very different.

I've since had conversations with a number of my sister's photog friends and colleagues, and was surprised to learn that almost none of them have real backup systems in place. Most have their photos haphazardly scattered across multiple external hard drives, but they have no systematic backup system in place to keep everything backed up in real time. So when somebody tells them they can just buy a RAID drive and it'll magically keep everything backed up without them doing anything, they don't ask any questions and just go with it, when what they really need is something very, very different.

Everything what has been stated here is very true. Backups solutions existed since the beginning of time, heck, I remember having 500meg DAT types used for backup. However, the problem with backup solutions is user behavior, and that is users are either careless or too lazy to perform backups. I tell my brother or parents to use a simple backup even an external hard disk that plugs into their laptop, but how often do you think they back the data up?

RAID1 does not provide the ultimate solution, but I think that people are looking at the seamless solution. How often do I install a 3rd party backup software only not to monitor/manage the backups, failures, someone shuts the computer off, the server is down, etc.

I am in the process of putting together a file server (I used an old computer for this) for my parents where these files will be stored in RAID1. I want to go to a NAS like DLink DNS-323 but know that if one drive becomes corrupted that RAID1 won't do much. I will also use an external hard drive and probably use one of the client machines to back onto this drive as well (3 drives containing the same data).

The ideal would be to set up an online service as well, however these are our private photos and I am kind of hesitent to release them into online space (our lives are on there).

Offsite solutions are the key, but then again if the house burns down we are down all the old photos from the 60,70s,80s, etc.

Mozy is a very good backup solution for most people, far better than RAID as long as you have an upstream internet connection fast enough to keep up with the amount of data you add.

It's real, automatic, incremental, encrypted, offsite backup. It has unlimited capacity. And it only costs $5/mo.

I have Mozy on my desktop computer with a very big hard drive and make the drive available over my home network to our other computers. And I just make sure that anything important gets copied to the desktop computer, so it gets swept up to Mozy during the nightly backups.

I actually thought about getting a DNS-323, but you can't run Mozy on it and Mozy Home won't backup network drives. So I just built a cheap desktop with XP Pro instead and turned on file sharing for essentially the same effect.

I'm thinking about using a similar setup for my sister using a Mac Mini with a Drobo (for big, expandable capacity) shared over her home network. She'd store her archives on the Drobo, and the Mac Mini would share it on the network and back it up every night (a Mac Mini is kinda overkill, but we need something that will do reliable AFP filesharing for the drobo and run Mozy, and it seems like an easy solution). But I'm concerned that her upstream pipe isn't big enough to handle backing up all her photos. Now if they'd just put FiOS in her building....

Your issue probably isn't the bandwidth, it's the overall transfer limit allowed by your ISP. A modern SLR takes big pictures and if she takes a lot, there will likely come a point where she hits the bandwidth cap.

Of course, you're missing one big thing here. She has to be able to recover the data. If you get a FIOS and it just enough to back up one day of data, then what happens in a year when her machine crashes and you have to restore (restoring with Mozy is a PITA I've done it) a years woth of data? How long will that take? What happens if it screws up halfway through?

She's probably better off manually backing up at the end of each day and keeping it offline in a safe or something. She could also take another weekly backup and keep it in a another house/office.

Her time to recovery is what you're not considering. Her data is her business. What's she going to do when people are waiting for wedding photos and she has to explain what Mozy is and they are being recovered.

Mozy is a great solution for regular people who have a few family pictures, tax returns, word documents, etc. It is not a great solution (unless they're willing to quickly overnight you your data on hard media) for a professional photographer who shoots in RAW.

As most have mentioned, RAID is for redundancy but not for backup. A RAID 1 or 5 array will allow you to suffer a single drive failure with almost no downtime. But so will several sub-$100 software products that make image copies onto a second drive. This can be quite fast if it's an internal drive in your computer. Personally, I use Power Quest's Drive Image 7 (no longer available - it was eaten by Symantec), and have restored my main drive twice quite easily. My big internal drive holds 7 copies of my work drive and rolls off the oldest copy with each new one. All automatic, kicks off each night. Additionally, a 1.5 Tb drive is attached to the USB port of my D-Link DIR-655 router, and a differential backup (changed files only) is made to this each night from my computer and my wifes.

Automatic solutions for backup are the only ones most should consider, as people rarely get religion about backing up until a catastrophe hits.

Something worth considering in evaluating backup solutions is the longterm viability of the system. I recently dealt with a small company that had a system failure that took out their server and tape drive. Of course, they had backup tapes - Travan 20/40. You can't buy this drive anymore. We had to buy a used one to recover.

You might ask yourself how long Mozy is going to be around. Perhaps for 20 years, I don't know. But the history of startups and shutdowns of internet companies is not encouraging. I assume they would give you ample time to get your data back if they were going out of business, but you never know.

Best to always have a local backup even if you backup online.

Of course, you're missing one big thing here. She has to be able to recover the data. If you get a FIOS and it just enough to back up one day of data, then what happens in a year when her machine crashes and you have to restore (restoring with Mozy is a PITA I've done it) a years woth of data? How long will that take? What happens if it screws up halfway through?

I believe you can pay Mozy to burn all your data on DVDs and FedEx them to you, so you get everything in a couple days. Have you tried that? You can also restore individual directories rather than doing full-volume restores, so if there were particular things she needed to prioritize, she could pull those down first.

We've thought about doing backups to external drives and rotating them offsite, but my sister is not particularly diligent about this sort of stuff and needs something very automated. Ideally we'd use Time Machine, but Time Machine requires a single target volume to back up to (it can't span volumes), so we'd end up needing a RAID/JBOD/drobo setup to back up her volume of data, which will probably exceed 1TB. Rotating full RAID/JBOD/Drobo arrays offsite will be very cumbersome and expensive.

Anyway, thanks for the input. I didn't mean to hijack the thread...

For home purposes, I think RAID-1 is the way to go, simply because the odds of finding a good/fast RAID-5 controller without paying thru the nose is minimal.

Worse problem: With the growing size of disks, RAID-5 no longer gives you very good odds on saving your data in the face of a disk failure. Why? Because when you do a rebuild, every sector on every remaining disk has to be read back, and with today's disk sizes, chances are that you will encounter bad sectors during that process. (Do the math. Vendors typically state an estimated rate of one bad sector per 1E15 reads.) What happens then? Well, that depends on your controller. If you're lucky you'll just end up with one corrupted RAID stripe. If you are less lucky, the controller will simply give up and abort the rebuild.

Above 500 GB or so, you really want RAID-6 or multidisk RAID-1.

But back to the OP - is there a case for RAID at home? Well, perhaps. Even if you have a really excellent system for automatically backing up your data every night, Murphy states that you will suffer a disk failure late in the evening after having had a tremendously productive day. A RAID setup could potentially save your day.

RAID doesn't replace backups, as we know. But neither do backups replace RAID.

However, RAID 1 and 5 are backup solutions, just not offsite backup. RAID 0 is the only one that does not offer that.

Please, please, don't confuse the two...



RAID is a fault-tollerance technique. One drive dies and you don't lose your data.

It is NOT a backup technique. Delete a file from the raid set and it's GONE.

-----Burton