RAID Trust Issues — Windows Or a Cheap Controller?

NicApicella writes "My new system has two sparklin' SATA drives which I would like to mirror. After having been burned by a not-so-cheap, dedicated RAID controller, I have been pointed to software RAID solutions. I now stand in front of two choices for setting up my RAID: a Windows 7 RC software RAID or a hardware RAID done by the cheap integrated RAID controller of my motherboard. Based on past experiences, I have decided that only my data is worth saving — that's why the RAID should mirror two disks (FAT32) that are not the boot disk (i.e. do not contain an OS or any fancy stuff). Of course, such a setup should secure my data; should a drive crash, I want the system up and running in no time. Even more importantly, I want any drive and its data to be as safe and portable as possible (that's the reason for choosing FAT32), even if the OS or the controller screw up big time. So, which should I choose? Who should I trust more, Microsoft's Windows 7 or possibly the cheapest RAID controller on the market? Are there other cheap solutions?"

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FAT???

[whoever57]

You data is most important and you plan to use FAT? Good luck with that!

Seriously, though. No RAID solution that is not totally S/W is portable. But do you really need RAID? It sounds like what you need is a good backup solution with frequent backups. Does you data change so much that losing one day's worth of data would be a problem?

Re:FAT???

[JustinOpinion]

I'm no expert, but it seems that RAID1 doesn't provide as much safety as some people think, because corrupted data just gets copied twice, so now you have two copies of the corrupted data. Same with accidental deletion--both copies are gone.

If all you want is multiple copies of your data, then really what you want is an automated incremental backup system, that copies your files to a second hard drive, and ideally keeps a few older copies so that if a file gets accidentally deleted or somehow corrupted, you have a chance to go back and find a usable copy. This is what I do on my system: I keep multiple incremental copies from the last few days/weeks/months. It was easy to set-up (in Linux, mind you). Do hourly syncs if necessary.

Also critical, if the poster is truly concerned about never losing data, is to get some kind of offsite backup. Two hard drives don't do you much good when the computer is stolen or your roof leaks. You need to have a way to regularly copy data offsite (ideally automated over the network, or via external hard drive if you're sufficiently disciplined).

RAID has its uses, to be sure. But if the poster is most worried about never losing important user files, then it seems like what he wants is is the multiple-redundancy of backup, not the immediate failover of RAID.

RAID != BACKUP

[Jave1in]

RAID is not a backup. Get a backup solution or you'll realize you can be even more frustrated.

RAID is *NOT* backup!

[pipatron]

You sound like someone that need to be reminded that RAID IS NOT BACKUP! Google for that sentence. All you talk about is saving your data, and RAID will not do that for you. You'd be better off just using the second drive as a backup. RAID will not save you from accidental overwriting of data, corrupt filesystems, broken chipsets, etc. The only thing RAID will save you from is downtime. If you lose that much money on the downtime it takes to recover from a backup, then by all means, use RAID, but don't treat it as a backup solution that will protect your data. That's not what it's made for.

RAID is never about protection.

[MajikJon]

RAID1 serves only one function. Increased uptime. If avoiding having to spend 2 hours restoring from a backup is your primary goal, then RAID1 might make sense for you. Do you have an office full of workers that will all lose productivity if you have a system crash? If so, then RAID may make sense. Any other use of RAID1 is fool's gold. It will not protect your data from a system-level problem. It will not protect your data from corruption (especially not on a FAT32 file system, which was never intended for any partition size above 32GB in the first place). It will not even always protect you from a single drive failure, since the rebuild process in a RAID1 setup often kills the second drive while trying to recover data. As many have said already on the thread, RAID is not backup. Backup needs to be a completely independent device. Unless you have serious uptime considerations, RAID1 should not be part of your backup strategy.

You are asking the wrong question.

[mcrbids]

RAID is only marginally valuable. In my experience, for all but the most carefully controlled environments, RAID simply adds complexity, the number of things to go wrong increases, along with the likelyhood of lost data. Do it only if you want the *experience* of running RAID, but don't count on RAID to "save your data".

I've worked as a system administrator for more than a decade, in medium-large scale deployments with good success, (think: servicing thousands of users, hundreds of domain names, tens of thousands of email addresses, etc) so I think I have some useful experience you can benefit from.

IMHO, you most likely to lose data from the following things (in order)

1) Aw sh1tz. "I didn't mean to delete that folder"... or "Whoops! I formatted the wrong drive", "I saved the wrong version of the file!", whatever. Although I *myself* don't have this happen often, it does happen. And even in my case I've lost about as much useful information this way as by drives dying. Users delete stuff all the time, and it's usually my job to bring it back, which is why I perform redundant, historical backups EVERY SINGLE DAY.

2) Malware. Don't minimize this - it's real, and it's why I reply to Parent. You are more likely to lose information from a virus/worm/malware and/or b0rked install of something that hoses your filesystem than by a hard disk crash given stable hardware.

3) Bugs. Filesystems have bugs. So do applications, utilities, anything with software. Strange, unexpected conditions, often caused by bugs in applications can cause data to "disappear", files to get corrupted, filesystems to get corrupted, folders to be incompletely written, etc. This is about as likely to cause lost data as:

4) Hardware failure. This is one of the lowest orders of lost data, although when it happens, it can be one of the most extreme.

Let me say this: RAID 1/5 only PARTIALLY protects you from the last one. Actual, bona-fide backups protect you from all of these. If you care about the data, get backups. If you care about uptimes at great expense, RAID *may* be worth it.

My advice is something most people don't want to hear: for personal use, get backups online for $5/month. Mozy/Carbonite/etc. There are zillion vendors, just Google it. In two years, it will cost you about as much as that 2nd hard drive. It protects you far better than that 2nd hard drive, and it's so automatic that you'll hardly notice it until the moment it actually matters: when you just have discovered that your data is gone.

Re:You are asking the wrong question.

[InsertWittyNameHere]

Your 4 points are correct. However, the reason for using RAID is NOT as a backup. RAID != Backup.

RAID is for redundancy and performance increases.

I had a drive die in my NAS a few weeks ago. It took 5 minutes to walk to the server room and plug in a new drive. There's no added complexity for the sysadmin, everything is done automagically by the RAID controller. Losing a server or data for hours while the drive is restored from tape is more expensive and complex.

Re:You are asking the wrong question.

[aneamic]

I'm sitting here laughing at the idea of backing up 1TB at internet speeds, rather than spending 60 bux on a 1TB external drive.

Re:You are asking the wrong question.

[highways]

5) Theft. Break-ins do happen and no amount of RAID will protect your data from that.

Re:You are asking the wrong question.

[jon3k]

Remember that you don't have to backup 1TB every month, just the changes to your files, which for most people are very minimal. You don't need to backup your entire collection of movies from thepiratebay, just important documents, photos, things that can't be replaced. And then you only need to upload every month the new important files, or ones that have changed. These deltas for most people are probably less than a gigabyte. Assuming a 1mb/s upload speed would take less than 3 hours _PER MONTH_ to upload. Now just schedule your backups to run nightly while you sleep and I think you'll be just fine.

Re:Seriously?

[morgan_greywolf]

The article smacks of false dichotomy. There are a number of solutions, not just Windows 7 or a hardware RAID controller.

To begin with, every NT-lineage Windows version ever produced supports software RAID out of the box. Add that to the fact that any major Linux distro today supports software RAID. And so do the *BSDs. And Mac OS X. And Solaris. And probably a bunch of other platforms I can't think of right now.

Hell, you could buy one of these one of these and throw the drives in it, connect it to your network switch, and presto -- instant RAID+NAS.

I think we would all like to know why you think Windows 7 is your only option, because if that's what you think, you don't know how mistaken you are.

Re:Seriously?

[gdshaw]

The article smacks of false dichotomy. There are a number of solutions, not just Windows 7 or a hardware RAID controller.

Agreed.

As I see it, if you want guaranteed repairability then you basically have two options: enterprise-class hardware with a support contract (and price tag to match), or an Open Source software solution.

Put another way, either you pay someone to take responsibility for fixing it, or you take responsibility yourself. A Microsoft solution doesn't give you enough control to take full responsibility, because you can't be certain that it will be legally or technically possible to recreate your current setup in five years time.

Re: online backups

[King_TJ]

Personally, I haven't yet encountered anyone who really got benefit from those personal Internet backup services like Mozy. In regular use, it always seems like the person exceeds their storage allotment or Internet connectivity issues prevent them from recovering what they need, when they need it.

I tend to recommend people buy an inexpensive external USB or firewire drive, leave it attached and assigned as a backup device, and have some software package run a daily backup of all the relevant folders and files they might need to save.

It's great that your data is stored offline and off-site ... but I'm just not sold on most of the implementations for "home use" being as great a solution as they first appear to be. Many of the providers have come and gone over the years, too. What happens when your offline backup company goes under?

Re:Just remember the first rule of RAID 0

[nemesisrocks]

Raids work best when every disk in the array is the same model and revision. If you plan to build a 5 disk raid array you should also purchase a 6th drive to keep as a cold spare.

I hate to break it to you, but you're actually wrong.

A RAID array is most effective using completely different drives, but of the same capacity. Five hard disks from the same manufacturer, of the same model, bought at the same time means that you're highly likely to get five drives from the same batch. Let's posit that there was some defect in this batch. Now all five of your drives have a significantly higher probability of failing at the same time. Oops! RAID can only deal with one (or two) drive failures!

Using drives from different manufacturers or model lines means you spread the risk of simultaneous drive failure.