RAID 1 to non-RAID

iworms

Hi, I want to set up RAID 1 mirroring at home. My goal is when one drive fails, I can continue using my computer before I get a replacement drive. I'll use a RAID card, not software or fake RAID. Since RAID card + battery unit ain't cheap, there's one thing I need to find out before I commit.

I know with RAID 1, if one drive fails, the array continues to function, and when a replacement is added, I can rebuild the mirror. But what if the RAID card dies? I hope I can continue with one drive non-RAID for a few days until a new RAID card arrives, with all the changes transparent to the OS. Will I be able to do that?

Thanks.

Hyper-Me

If the entire card dies then usually essential array information is lost.

RAID 1 is used for redundancy but remember that its not a backup solution and its not fail-proof.

tiersten

iworms wrote: »

But what if the RAID card dies? I hope I can continue with one drive non-RAID for a few days until a new RAID card arrives, with all the changes transparent to the OS. Will I be able to do that?

Depends on the RAID controller you're using if you can just take the drives off the controller and use them standalone.

Even if the HDs do contain a complete copy of the data without any weird RAID controller headers or partitioning scheme, it won't be transparent to the OS when you do this. It may not appreciate the fact that the boot drives now exist on a different controller and that it is no longer RAID.

What Hyper-Me said anyway. RAID isn't backup. It just protects you from a specific number of simultaneous drive failures. If this data is that valuable then back it up.

iworms

Thanks for the answers, guys. For data backup, I'll do that separately. My concern is actually how long before I can use my computer and resume work again.

With my single drive now, if the drive dies, I won't be able to use the system until I restore the backup to a new drive -- too slow if a deadline is coming up.

With a RAID 1 dead card, if I can't simply remove the card and boot Windows from one drive (maybe with 20 minutes of tinkering) to finish the work, then it's not that attractive anymore. It just moves the single point of failure from the hard drive to the RAID card.

Hyper-Me

It does, but the likelyhood of a quality RAID card with no physical moving parts dying is a heck of a lot lower than platter disks.

Want a HD that likely wont die? Get an SSD.

tiersten

Hyper-Me wrote: »

Want a HD that likely wont die? Get an SSD.

The generally available consumer SSDs don't have a 100% reliability record at the moment. There have been many reports of nearly every brand of issues with the firmware for the controller inside.

tiersten

iworms wrote: »

It just moves the single point of failure from the hard drive to the RAID card.

Its more $$$ since you need two controllers but look into duplex RAID.

Any particular reason why you don't want to use software RAID? Unless you get an expensive RAID controller, software RAID with a decent CPU will most likely out perform a hardware RAID controller. You don't have the issues with the controllers either since you can just use another port or get another motherboard. You should be able to just boot off a single drive as well if the other one fails and the OS shouldn't freak out.

dynamik

Do your work in a VM and back up the VM. You can then reload your system on any machine where you install whatever virtualization you're using.

Edit: I run software RAID on my EP45-UD3R and get excellent performance. Mirror for the OS and RAID-10 for data.

crrussell3

Another option would be to do a full drive backup daily (or whenever you deem necessary), so in case of a HD failure, you can slap in a replacement drive that is just sitting there and restore the backup.

tiersten

You could get a spare HD and a spare RAID card. Your single point of failure them moves to one of the other PC components which you'd need to keep spares of. Windows probably won't be too thrilled at you if you change the motherboard either. There is just a point where you have to accept that if X components die then the machine will be out of action until you can purchase or acquire replacement parts.

Hyper-Me

tiersten wrote: »

The generally available consumer SSDs don't have a 100% reliability record at the moment. There have been many reports of nearly every brand of issues with the firmware for the controller inside.

I havnt heard quite that many complaints but there are certainly major quality gaps between certain brands, etc out there right now.

Forsaken_GA

It'll largely depend on the raid card as to whether or not you can pull it off the card and allow it to be used as a standalone drive. I know for sure that the 3ware 8006's and a few of the 9000 series cards will allow their raid1 drives to come off the controller and function as standalones.

I prefer to do software raid for raid1 though, as there's virtually no performance hit, it removes a point of failure, and in the Linux realm at least, the drives are very portable

iworms

tiersten wrote: »

Any particular reason why you don't want to use software RAID?

tiersten wrote: »

You should be able to just boot off a single drive as well if the other one fails and the OS shouldn't freak out.

tiersten, by software RAID (in Windows), should I do 1) dynamic disk in Windows, 2) 3rd party (Intel?) software/driver, 3) 3rd party cheap controller with software/driver, or 4) BIOS feature with 3rd party software/driver? Sorry, I've never used RAID before. It'd be nice if you could give a link or two on setting up software RAID

I looked into dynamic disk, and while I will be able to boot a single mirror, the data is readable only in Windows itself (probably not even to another Windows machine if I put the drive into a USB enclosure).

Thanks!

tiersten

Hyper-Me wrote: »

I havnt heard quite that many complaints but there are certainly major quality gaps between certain brands, etc out there right now.

I've heard bad things about the early JMicron based ones, some of the Intel ones and some of the Indilinx based ones.

I've got an OCZ Vertex in my laptop which is a reference Indilinx IDX110M00 design with a branded firmware. There have been many bugs and issues along the way as Indilinx and OCZ have released firmware that either requires a destructive format to upgrade or had data corruption issues.

Intel have had issues previously with buggy SSD firmware which caused laptops which used the ATA security features to lock out the drive. I know a few people which have had their Intel X25-Ms totally fail and require a RMA.

The consumer SSD market is still fairly new at the moment so I'd expect some teething problems. The only issue is that there appear to be more companies entering the SSD controller market so you might actually be buying a 1st generation product even though it is from an established company with an existing series of SSDs. Intel, Indilinx, JMicron, Marvell, SandForce, Samsung and Toshiba are the companies I know that make consumer level SSD controllers.

msteinhilber

iworms wrote: »

With my single drive now, if the drive dies, I won't be able to use the system until I restore the backup to a new drive -- too slow if a deadline is coming up.

How much time before you are up and running again is acceptable? What are your consequences of your downtime, how much money does it cost you, etc? You mention a deadline so that leads me to believe this is either for your workstation on the job or for a workstation you use for business at your home. If this is a professionally used machine, not one for home use then the solution you implement should be implemented with the value of your uptime in mind.

That being said, as others pointed out - a RAID controller failing is much less likely than a drive failing. Depending on the load of this computer, you might be able to get by with a fairly affordable RAID controller that isn't hardware based. Many of the cheapest controllers like the Silicon Image based units for example will boot to the working drive if you are running a mirrored configuration. The controllers are so cheap that if you are that concerned about a controller failing that you could keep a spare on hand easily.

If this is something more mission critical for you like it's sounding like from the statement I quoted, then you should really have a second workstation you can use that's always ready to go with the requisite OS and programs loaded. Maybe you could consider setting up a NAS at home and keep your data mirrored both on your local workstation(s) as well as the NAS. If your primary workstation fails, hop on your second workstation and continue to work with the data located on the NAS while you bring your primary workstation up and running. If you want to go a disk image backup route, you can use the VM method dynamik suggested or you could use something like Acronis. With Acronis, you can license it with Universal Restore and use your backup image to restore to dissimilar workstations.

There really are dozens of options, some inexpensive and fairly effective for a home or small office use and some that are very expensive that are more suited to the enterprise. You have to determine how important your ability to do whatever it is you do on your workstation is to qualify how much money you invest and how much downtime is realistically acceptable.

tiersten

msteinhilber wrote: »

Many of the cheapest controllers like the Silicon Image based units for example will boot to the working drive if you are running a mirrored configuration.

Are they actually hardware RAID though? I thought they were handled RAID from the firmware on the card?

msteinhilber

tiersten wrote: »

Are they actually hardware RAID though? I thought they were handled RAID from the firmware on the card?

They are fakeraid, I didn't know if the OP had a requirement to go with hardware over fakeraid.