RAID Trust Issues — Windows Or a Cheap Controller? 564
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?"
Your first problem is Fat32 (Score:5, Informative)
If you want data integrity, use NTFS. Using Fat32 is like saying you want a reliable car, so you're buying a Edsel because they've been around a long time-- it doesn't make sense. Every other OS on earth can read NTFS (if not write it), so it won't affect your portability requirement.
Secondly, before you make any decision regarding Windows 7 RAID, make sure the edition of Windows 7 you want to buy ships with software RAID support before you put all your eggs in that basket-- early betas and RCs of Vista had software RAID enabled, only to have it disabled before release. I've seen no guarantees about Windows 7 software RAID support, and which editions will have it enabled. (If any.)
If you're planning to move to a server OS after Windows 7 expires, I can practically guarantee software RAID will be enabled, but that still doesn't mean you can necessarily upgrade your Windows 7 software RAID array to a Windows Server software RAID array. Do your homework.
It's *NOT* hardware raid on your motherboard. (Score:5, Informative)
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.
RAID is no substitute for backups (Score:4, Informative)
RAID is no substitute for backups. RAID is very good at propagating errors and problems very quickly, be they software glitches or human errors.
For consumer class storage, weekly / daily backups might be more efficient than investing a lot of effort into live RAID. Since I'm a Mac guy, I see the best answer to this question as Time Machine to a network / USB attached drive -- hourly (configurable for more or less often) differential backups, almost transparent to the user. To my knowledge, Windows has no similar set of software to allow reinstallation to the last hourly backup -- my wife had the misfortune of having to restore a blank drive from her last backup and it was a flawless process that truly left her where she left off less than an hour before the hardware failure. The reinstall wizard just had to ask where the backup was. Casting aside MacOSX advocacy, there is truly no substitute for a good automated backup solution that is regularly tested. I think the best method would use the fewest common components, like a NAS, followed by an external drive with its own power supply. My least favored option would be an internal drive with every single component shared.
Re:Just remember the first rule of RAID 0 (Score:5, Informative)
Re:Just remember the first rule of RAID 0 (Score:5, Informative)
Actually, it depends on the reliability. 95% reliability becomes 90.25% reliability. 50% reliability becomes 25% reliability. 1% reliability becomes 0.01% reliability.
So if your drives are very reliable, it's very slightly less than twice the failure rate. If your drives are not reliable, then it asymptotically approaches an infinitely greater risk of failure.
Statistically speaking. :)
Re:FAT??? (Score:2, Informative)
The big problem in this picture is the way that Windows deals with drive errors. It doesn't report them and people commonly discover that one of the drives in a mirrored pair is dead when the second drive dies and leaves them with nothing.
The only way to seriously protect data is Multiple methods of backup and multiple media.
Plus you need to remember that a common first sign of a drive failure is the backups start to fail. If you don't notice it and keep swapping media, pretty soon you have a media set with no backups on it.
RAID is a high availability feature, not backup (Score:2, Informative)
Consumer editions of Windows only ever supported Software RAID1. I've made a few experiences with SW RAID1 on WS03, and it's pretty much crap. Linux SW RAID on the other hand worked fairly well.
RAID is not a backup. This is the most important observation. RAID is a high availibility feature. If you lose your RAID array, you shouldn't lose any data. If you do, your backup strategy sucks.
Generally, skip RAID in a consumer setup. RAID is complicated, it's a PITA and especially the low end stuff can do more harm than good. Even expensive stuff can fuck your shit up (I'm looking at you, ServeRAID 8k). Better in invest in a proper backup - to a local harddrive and maybe offsite. Online backups make sense in a home office. For servers, i recommend LTO tapedrives.
Re:Be Careful (Score:5, Informative)
What RAID is good for:
Better to just throw a disk in an old machine and back up to it regularly.
External eSATA enclusure (Score:2, Informative)
Re:On board all the way!! (Score:3, Informative)
Fakeraid is software too.
Get a real hardware RAID controller, or don't use RAID. Windows SW RAID or a Fakeraid controller is just plain stupid.
Re:Have some FUD with your RAID (Score:2, Informative)
Yeah, blame broken applications on the filesystem. Seems like a good idea.
Re:It's *NOT* hardware raid on your motherboard. (Score:5, Informative)
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:RAID1 is not fool's gold (Score:3, Informative)
Re:FAT??? (Score:5, Informative)
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. (Score:3, Informative)
Having run RAID quite a bit myself one must remember having all your drives in one box is always an invitation for trouble since hardware failures on a higher order will likely hit all the drives.
If you want to do online backup get DSL instead of cable internet for the faster upload bandwidth.
Get a backup service with versioning. That way if you or a virus delete something it just doesn't sync the deletion to your backup.
I personally use JungleDisk which uses Amazon S3 storage. You can set the versioning controls and you only pay for the storage/bandwidth you use. My bill averages about $2/mo for several gigs.
RAID (Score:2, Informative)
You're in a special situation using Windows 7 RC. So despite the below, you're especially at risk to the possibility of a new (but not yet discovered) bug in Windows release-candidate software, don't use Windows or other RAID capabilities for your "data protection", use backups. Use RAID mirroring for improved performance or to reduce the probability of downtime occuring, and allow for rapid recovery from common drive failure scenarios.
RAID controllers (Software or Hardware), all suffer from various scenarios where the entire array can fail, and data recovery becomes so hard that it may as well be lost. 90% of the bits may be there redundantly, but you can't get to them for one reason or another. Also, RAID will not protect against system compromise, software data corruption, accidental deletion, or any type of volume corruption that occurs as a result of software running on the system.
Don't pick FAT over NTFS on the basis of portability between systems, if reliability is more important, the NTFS filesystem uses a technique called journalling which makes data corruption less likely after a system crash, eg power failure. NTFS _can_ be read by common solutions, if you need to recover data. Recent Knoppix CDs and various rescue disks can read NTFS, and the filesystem checking tools available for NTFS filesystems are better. FAT is more susceptible to certain failures, including excessive fragmentation leading to poor performance.
Research what type of RAID solution your integrated hardware really is. If it is hostraid, or fakeraid, that requires Windows drivers to implement RAID, then don't use that, avoid like the plague as it's SOFTWARE RAID, even though the software is running inside a driver provided by the controller vendor and A FEW functions may be offloaded to hardware, the main RAID code is still running in software, which is bad, mmmkay?
You can often detect this in that there will be Windows only drivers, or the product will be labelled a hostraid solution, but each of the major drive controller/RAID chip manufacturers has a different name for their ultra low-end solution that isn't really hardware RAID, but has hardware offload of just some functions (checksumming, mainly).
(Fakeraid/Hostraid adapters that require special drivers in the guest OS to implement RAID, also generally suffer from the RAID5 write hole if you utilize RAID5. And RAID code may be more susceptible to certain problems, when it isn't running on card firmware.)
I would actually favor implementing RAID in Windows over that. However, there is hardly any point of doing this, except if you are mirroring your boot drive, or you need RAID for improved performance (e.g. You could use RAID1 for all drives to improve read speeds, RAID1+0 to improve both read and write speeds, or RAID5 for redundancy and scalability at the cost of slower write speeds and a read speed penalty).
I mean that: since you aren't mirroring your boot drive, there is little point of utilizing RAID in your case. One of the most performance-effecting files on your disks is the page file on the boot drive. If you were utilizing RAID for improved performance, you should definitely want to maximize read and write speeds to the boot drive.
If your non-redundant boot drive crashes, your system will be down and need to be re-installed on a new system drive. You may as well just pre-image a backup drive with your system, keep a continuous backup on another machine, and in the event of a failure, pop in the backup HD, and start restoring continuous data from backup, to bring your 'spare' up-to-date.
This will probably even be faster, as an OS reinstall and re-up of Windows is not required
Second, your RAID controller can fail, make sure you have a plan. That would mean either two identical controllers with the exact same firmware version, or you use a very common controller that you are CERTAIN you can easily buy anoth
Re:Just remember the first rule of RAID 0 (Score:5, Informative)
And what allot of people don't realize is if you build a RAID array and a drive fails can you replace the drive with the exact make and model? 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 built a RAID 5 array using three 500GB disks via mdadm under Linux. I assembled the array and formatted it. Within minutes of testing I was getting mail from mdadm telling me the array was degraded. I then began to test each disk for defects and lo and behold one disk was bad right from the start. I tried to RMA the disk but newegg had informed me those disks were now obsolete. Great. I was credited for the bad disk and purchased a new one that closely matched the other two. It was a nightmare as during some boots the disks went haywire and I would get a "Could not bd_claim sdaX" And it would hang for a while and I would have no array. It happend once in a rare while until it became a real problem. I kept my most precious data safely backed up on different disks I had spread around. It finally got so bad that I would have to constantly reboot the machine for up to ten times before the disks were synced up and the array worked. I purchased a 1TB disk and copied all the data off the array to it and used the 500gb disks in other systems. RAID is great for big fat storage arrays but it can become very sensitive and then one day POOF its all gone.
This is the reason OEM drives from Dell, Apple, HP etc. Cost four times what a retail drive would cost. The cost is no way associated with quality but rather consistency. Retail SATA drives are constantly changing: less/more platters, faster seek and read speeds and firmware revisions. Those costly OEM drives are the same disk every time right down to the inner workings and firmware. So if you buy an Apple 1TB disk on a sled and it takes a dump in three years you can be confident Apple will replace that drive with the EXACT same one. Its not a magical Apple disk of superior quality but a Maxtor/WD/Hitachi disk that is produced for Apple with no revision changes unless Apple orders it. Unlike retail drives which are changed at the manufactures whim.
So if you are building your own raid plan for failures and try to buy a spare for your array. I don't know disk shelf live but it will save you down the line. Also keep a USB or 1394 disk around for backups. Spread your most precious data around like pictures home movies and documents. If you have a few computers around the house keep a mirror of that data one those machines. Music, and downloaded video can be re downloaded but home movies and pictures cannot. Put all the silly stuff on the raid along with the precious stuff for access but keep backups of the good stuff!
Re:Just remember the first rule of RAID 0 (Score:5, Informative)
Re:Just remember the first rule of RAID 0 (Score:4, Informative)
Do you have any evidence for this claim?
A typical RAID implementation writes stripes at a time, by issuing a series of writes to each drive. If your disks have the same geometry, then each write will be at the same physical location on each drive and so complete in almost exactly the same time. If they are not, then the different disks will be moving their heads at different times. The RAID controller (hardware or software) will then be bottlenecked by the slowest drive. To make things worse, the slowest drive can be different for each write. One write may require moving the head sideways on one disk, the next may require moving the head sideways on the other. In both cases, you are limited by the worst-case performance for the disk. The same is true for reads on RAID-5, but not RAID-1, which can just use the result for whichever disk returns first.
Re:You are asking the wrong question. (Score:3, Informative)
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.
I don't think this is quite right. Hardware fails all the time, it should not be underestimated, and often it is useful to augment backups with RAID. It just depends on your exact needs... what is this data? Does the world end if you can't get back up and running within an hour of a hardware failure? If 12 hours of downtime is ok, then restoring a backup, is of course, more reliable, but you may have lost data between the time the backup was taken and the system crash.
Latent defects on hard disk drives are extremely common [pcworld.com], and can actually cause software failures (Are you sure your "NTFS" corruption is a NTFS bug and not a latent disk error?). Actually, silent data corruption is a lot more common than complete failure, and RAID may not even be sufficient. Just ask the folks at CERN who ran fsprobe on their drives, and detected scarily high rates of corruption on common drives.
My preference is not to run important storage on Windows, but to utilize technologies like Solaris and the ZFS filesystem, which can detect and recover from such corruption. But RAID arrays do often support some method of checksumming and periodic verifications, to assist with preventing such errors. Using RAID or some type of redundancy solution is a lot better than utilizing standalone drives, when data integrity matters.
Accidental file deletions do happen, but it's usually on workstations. Usually accidental file deletions have limited scope, and recovery is possible without a backup, by imaging the disk, and using various repair tools.
However, say on X site's 1000 user mailbox Exchange server, a trained sysadmin is not likely to accidentally delete C:\windows, or something like that; a hardware failure is one of the things that is most likely to have a wide impact (second only to a misconfiguration, software failure, or admin mistake). Yes, there can be software bugs, but NTFS is basically rock solid, filesystem corruption is extremely unlikely on modern server OSes.
It would basically be foolhardy to not at least utilize run RAID1 (if not RAID1+0 with a hot spare and 5 or 6 separate RAID LUNs for boot drive, data drives, log drives) on such a critical server, because HW failure _really_ is one of the few major failure modes.
Moving parts (HDs, Fans, Air conditioners, Cooling pumps) usually fail the most often, followed by the parts most exposed to unstable power (PSUs, UPS gear), parts that are electrically sensitive (RAM), and parts that generate high amounts of heat, CPU.
With proper security precautions, malware on important systems is rare or non-existent. Users may get infected with malware, but they don't have access permissions to delete critical files. Windows Volume shadow copy on servers with previous file version tracking is more than adequate for dealing with most situations there.
The newer, denser, high capacity SATA hard drives are even more likely to fail than the ones manufactured just a few years ago, especially when they are designed for workstation class application loads, and are being stressed beyond expectations (by demanding apps or new OS software).
Granted, having RAID setups with high performance needs, might be part of the reason so many hard drive failures are seen in datacenters.
If you have a 3 drive RAID 5, instead of a single drive, there is a massively increased probability that at least one drive will eventually fail, because there are 3 times as many hard drives, than if you had just one disk drive.
That's another cost you incur in order to improve performance and reduce the probability of HD failure causing data loss.
Re:Just remember the first rule of RAID 0 (Score:5, Informative)
All modern disks remap sectors as necessary. The main difference between consumer and RAID drives is the timeout for error correction [wikipedia.org].
Re:Just remember the first rule of RAID 0 (Score:2, Informative)
Ah, but when you buy a few drives for your RAID array, with the same model and revision, and give them all very similar usage patterns, in the same exact location, then it's a lot more likely that more than one drive will fail on you in quick succession. making your RAID array a lot less safe than it seemed at first.
Re:You are asking the wrong question. (Score:5, Informative)
Having run RAID quite a bit myself one must remember having all your drives in one box is always an invitation for trouble since hardware failures on a higher order will likely hit all the drives.
Not to mention the temptation to use _Identical_ disks in your redundant array... I've had a RAID1 pair fail totally when both drives died within 24 hours of each other because of a firmware bug. This happens a lot more than most people think. Statistical analysis of the reliability of RAID _always_ assumes failures arrive independently of each other, but a large proportion of failures are caused not by random events but by external circumstances and therefore happen either simultaneously or nearly simultaneously.
Re:Just remember the first rule of RAID 0 (Score:4, Informative)
Is it worth keeping a spare for the sole purpose of having the same model available in the event of a failure when you can get a newer and faster drive in the future?
I would say not, but when one drive fails you should replace all of them. For a home array, expect one drive to fail every few years. I had a disk in RAID-1 array fail last year. It was a 40GB disk which cost around £100 new. For the same price, I can buy two 500GB+ disks now.
Is the difference in performance between modern SATA drives so significant?
It's not a question of performance, it's a question of the difference between a linear access and a seek. The time for a seek is 4ms+. If a drive can read 50MB/s then a linear access is around 10 microseconds. If your one disk is doing a linear access while the other is doing a seek then you are limited by the time of the seek (for RAID-1 writes and RAID-5 reads and writes). If you have to seek after every block, your maximum throughput is 125KB/s. If you do a linear read, your throughput is 50MB/s. If your drives have different geometries, you double the number of seeks you are needing, dramatically reducing your throughput.
FAT32, Really? Protability, Really? (Score:2, Informative)
Promise SATA RAID = Cheap and Good (Score:3, Informative)
Raid will NOT secure your data (Score:3, Informative)
raid will make your data highly available, not secure.
if you want security, you need backups, and backups are:
- off line (viruses, power surge, sabotage...)
- off site (fires, theft...)
- tested (i've got horrors stories of people that THOUGHT they had backups...)
- multiple (... and of backups that turn bad at the worst possible moment)
Raid is none of that. I know plenty of people who thought their data was safe because they had raid. It isn't, it wasn't, it ain't ever gonna be.
Re:Cheep Non-RAID Controller! (Score:3, Informative)
My faithful old Linux home server runs two RAIDs, both in software: a RAID-1 for the OS (remember: the BIOS does not know about the RAID), and a RAID-5 for the data.
Beware of RAID-5, it's dangerous.
The problem is that reconstructing the array after a disk fails is a very intense operation that touches every sector of every disk. If another disk in the array has a latent failure, the reconstruction operation will trigger it, and when you lose two disks from the array, you're hosed.
This happened to me. I had a RAID 5 array with a hot spare, one drive failed and dropped out of the array, and the process of reconstructing onto the hot spare triggered another failure. Luckily, it was only a transient failure, and MD had e-mailed me reports that contained the order of the disks in the array before the second failure. By forcibly reconstructing the array (telling MD that it was "good" even though it wasn't) I was able to get the array running again in degraded mode. The second reconstruction attempt failed, but the third succeeded, at which point I removed the disk experiencing the transient failures from the array and reconstructed again onto a newly-purchased disk.
I have since switched from using RAID 5 plus a hot spare to RAID 6.
Re:Just remember the first rule of RAID 0 (Score:5, Informative)
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 [ssdirect.com] 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 (Score:5, Informative)
"That's nice, but the submitter is asking about RAID 1."
I think he's asking the wrong question anyway.
"Based on past experiences, I have decided that only my data is worth saving"
See? He is asking for backup, not RAID. It has been said one thousand times but it seems it must be said again: RAID is *NOT* in order to protect your data. NOT, NOT, NOT and then NOT again.
RAID (not talking about RAID-0) is there in order to enhance your data's avaliability (as in, say, instead of being able to get to my data 99% of the time, I can get to it 99,9%) but when it's hosed, it's hosed. To protect your data you need backups, not RAID.
"Of course, such a setup should secure my data"
Of course not. Of course you will get quite a funny face when you discover it. Quite more or less the one that had the guy from this story, about six months ago, with the very enlightning title "Why Mirroring Is Not a Backup Solution": http://hardware.slashdot.org/article.pl?sid=09/01/02/1546214 [slashdot.org]
"Even more importantly, I want any drive and its data to be as safe and portable as possible"
Then, *even* if RAID could be considered for data security (which is not) you already answered your question: as a general matter, hardware RAID will only work when using exactly the same controller model, possibly up to its minor revision. You can't count to break a hardware-managed mirror, take one disk to a standard SATA controller and get any data out of it. If your controller dies and miracolously doesn't take the disks with it you can't count on buying a different RAID card (as it will most probably be in about a year for consumer-grade hardware) and get any data out of the mirror. So you should go with software RAID.
AND TAKE BACKUPS.
Comment removed (Score:3, Informative)
Re:Just remember the first rule of RAID 0 (Score:5, Informative)
Why RAID is not a backup:
1) not fireproof.
2) not mistake proof "oops, didn;t mean to delete that"
3) not immune to file system corruption.
4) not immune to power supply failure/surge/lightning/other destructive forces
5) more expensive than a good backup
6) not protable offsite
7) does not track versionb history or old files (something that should be of critical importance to a programmer...
8) Viruses, mailware, hackers oh my!
9) bad/corrupt install
10) OS failure
I could easily go on. I worked in DR for 4 years...
Nearly all of the above have a higher frequency of occurance over a 5 year typical HDD life. Even if you continually replace drives without a data failure, you're still eventually going to have an issue RAID can not deal with.
My Qnap was a $399 device. The 4 drives in it were $90 each (and the 5th spare too). The HDDs I run the PC off on the RAID 1/0 were $40 each. I only run the RAID 1/0 for performance during video editing. I chose 1/0 vs 1 since 1 halves the reliabiltiy of the drives. Even though I do have a good recovery solution, the downtime, nor the effort involved in recovery, would be welcome, and the extra $80 to mirror the performance stripe was easily spent.
The Qnap is also my iTunes media server, my FTP server, included the price of the DR software, and runs 2 IP cameras I set up at home too (which let me tell the insurance company I have real-time video monitoring, and they knowcked an extra 5% of my homewoners policy cost, which by itself is enough to fund replacement drives as I'll need them).... Oh, yea, and it's a NAS too... It has a lot of value beyond a backup system.
I'm guessing you've not got a child yet, or a large family. You probably don;t value to pictures you take, files you have, and other stuff on your PC. That's fine, someday you likely will.
There are cheaper ways than mine to do backups. I have over a TB, and 3 (currelty, soon to add 2 Macs to the list an decom 1 old laptop leaving me with 4) computers I'm backing up, so centrally makes sense. If you have 1-2 machines, a small amount of data, and don't value most of it, then 2 external USB drives and a safety deposit box (Dad's house) usually suffice... Or, just an online backup account for $5 a month...
RAID 1 might save you from a firmware failure, or a disk going bad, but that's about it... Also, RAID 1 may be cheap, but a backup is cheaper. Also, good luck rebuilding that RAID if your MOTHERBOARD fails... RAIDs are proprietary to a particular controller. Unless your new board usues the same chipset (and firmware too in most cases) you;re screwed without a backup.
Forget about RAID. (Score:3, Informative)
> I have decided that only my data is worth saving
Then forget about RAID. RAID is designed to protect the integrity of the underlying volume - NOT the data that's on it.
> Of course, such a setup should secure my data; should a drive crash,
Then forget about RAID. RAID will only secure your data under some very specific cases of hardware failure of the drive. It does absolutely nothing towards preventing data loss due to (say) a corrupt file allocation table, virus, accidental deletion, or corruption.
> Even more importantly, I want any drive and its data to be as safe and portable as possible
Then use proper backups - not RAID. Preferably off-site backup. I use Carbonite which backs up to the 'cloud' at minimal cost.
By all means use RAID to protect you from hard disk failure, but don't under any circumstances assume it stops you losing your data. For backups, I always use the rule that at any given point in time, assume that the next time you walk back into your house/office, that NOTHING in that building is still there. Do you have a copy of everything you care about somewhere else?
I'm still amazed by people that carry 12 months of work around on a single floppy disk/USB stick/laptop, then cry when they go to the helpdesk asking what "sector not found reading drive A:" means, or perhaps "A USB device attached to the system is not functioning".
Get your data in as many places as possible - preferably three. A drive which is mounted one inch above the main one is *NOT* a valid second place!
Re:You are asking the wrong question. (Score:3, Informative)
Re:FAT??? (Score:3, Informative)
The big problem in this picture is the way that Windows deals with drive errors. It doesn't report them [...]
Windows reports drive errors in the Event Log.