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?"

Comments

Have some FUD with your RAID

[suso]

Do you really want to trust Windows with your data?

Comment removed

[account_deleted]

Comment removed based on user account deletion

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.

Re:RAID is *NOT* backup!

[Mishotaki]

Wait, are you implying that people should google their question before submitting it to /. ?

Are you insane?

It's *NOT* hardware raid on your motherboard.

[Zarhan]

These motherboard "raids" are called fakeraids.

All that it is is that it writes the metadata on the disk in specific format so that you can see the raid volumes via BIOS. Note: Only "see" their status - in case you replace one drive, the resync is still done by software and you must boot to operating system. One clue is the fact that in Linux the dmraid package uses exactly same driver for accessing fakeraid-mirrored drives and Linux's own software-raids - device mapper just does a bit of magic at init.

However, if faced with choice of Windows-only or motherboard-raid, I'd go with the motherboard-version, because that's at least supported both by Windows and Linux so in case something goes wrong with your Windows installation you can always pop in Knoppix or some other Linux CD for recovery.

Re:It's *NOT* hardware raid on your motherboard.

[Grishnakh]

DO NOT buy a real RAID card unless you have a pretty good budget for your system, and need the highest performance. The problem with buying a real RAID card is that you need to buy not 1, but 2 or better yet 3 of them, so that you can have spares. If your RAID card dies (and they do, more often than you'd think), the only way you'll be able to access that data, because of the proprietary on-disk storage method used by RAID card vendors, is to have an identical card (with the same firmware version, to be safe). And since hardware is constantly being obsoleted, you need to buy your replacements when you buy your card, not hope they're still available later. It's also a good idea to have spares of the same make and model hard drive, because hardware RAID controllers aren't usually that flexible in allowing you to pair up different sized drives like Linux sofware RAID.

For many purposes, software RAID using Linux is really a much better solution, because the on-disk format is open-source and standardized, so it doesn't matter what hardware you have, you can plug the disks into a different Linux system and you'll be able to read the data with no trouble. The only downside is a slight performance decrease since the CPU has to do all the work, but even then unless the system is heavily loaded, it's still faster than hardware RAID because the hardware RAID cards aren't that fast.

With the giant drives that are now common, I think the best solution, at least for home/desktop systems, is to forget about RAID5/6 altogether and just get a couple of 1-2TB SATA drives and mirror them with software RAID 1 in Linux.

Re:Just remember the first rule of RAID 0

[Anonymous Coward]

That's nice, but the submitter is asking about RAID 1.

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.

Kudos.

[denttford]

"Safe" FAT32, cheap RAID, RAID implied as backup, Microsoft.

Nice job, you successfully trolled the /. frontpage.

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:FAT???

[jeffasselin]

No. NTFS is not perfect, but to think FAT is as bad is deluded. I've honestly never seen a HD formatted with NTFS that I couldn't repair with built-in tools, unless it had physical defects, and in such a case ANY file system would have problems. But I've seen so many FAT drives get hosed by little problems, it's not even funny.

Seriously, don't trust your data to a FAT partition - not worth it.

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:Just remember the first rule of RAID 0

[Trebawa]

He wants to mirror the drives. This means he wants RAID 1. Therefore, the failure rate of the array is 1/2 the failure rate of each disk (more, actually, because they're like;y identical drives that will fail at the same time, but you get my point).

Re:You are asking the wrong question.

[Ant P.]

That's an interesting thing... the power supply has more potential to cause damage than anything else in the PC, but nobody ever thinks about protecting against its failure. Makes me wonder why we don't have surge protectors on the 5/12V rails as standard yet.

Re:Just remember the first rule of RAID 0

[mooboy]

Whoa, hold the boat. I've had a lot of experience with Dell & HP/Compaq(Proliant) provided RAID systems and they are not sensitive to disks with vastly different innards. All that matters is block count and software mirroring doesn't even care about that, because you'll simply be limited to the size of the smaller disk. If you're using mirroring or RAID, try to go with different makes of the same size. This article talks about MTBF. It turns out if 2 drives of the same exact model comes off the line and end up in your PC, there is a chance they could fail within a very close time to one another. So your mirror or RAID could fail permanently while rebuilding from the first failure. But if all your drives are of a different make, chances are they won't fail at the same time and you'll get the critical time needed to rebuild your array.

When I'm going to do mirroring or RAID on hardware that doesn't have high-end dedicated server RAID controller, I use Windows or Linux software RAID. Performance is surprisingly good and I'm not married to a specific hardware implementation. I've had _none_ of the issues you've described with Linux software RAID on several servers for several years. Mdadm has only whined after a power outage or genuine disk failure.

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.